Re: [CentOS] "power outage"-save / like embedded systems

[Leon Fauster]

Am 01.10.2014 um 00:53 schrieb John R Pierce :
> On 9/30/2014 3:42 PM, Leon Fauster wrote:
>> Sure, for servers but I am talking about a small
>> 9W-power-consumption appliance that have this
>> requirement:-)
> 
> I don't think CentOS is the appropriate distribution for
> that sort of system. Does it even have jffs2 support?


$ modinfo jffs2
filename:   /lib/modules/2.6.32-431.29.2.el6.x86_64/kernel/fs/jffs2/jffs2.ko
license:GPL
author: Red Hat, Inc.
description:The Journalling Flash File System, v2
srcversion: 8455E744807A823ED40A4E8
depends:zlib_deflate
vermagic:   2.6.32-431.29.2.el6.x86_64 SMP mod_unload modversions 



> a uClinux/busybox based system would be much more appropriate.
> maybe start with DSL, http://www.damnsmalllinux.org/ or tinycore,
> http://tinycorelinux.net/


the consumption of resources like memory and storage is not an issue.
The main reason to stay with C6 is our internal processes. Another 
distro to be maintained is not an option. I will check the 
implementation of the distros above ... thanks.


--
LF

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[John R Pierce]

On 9/30/2014 3:42 PM, Leon Fauster wrote:

Am 30.09.2014 um 19:08 schriebm.r...@5-cent.us:

>Leon Fauster wrote:

>>I would like to setup a small system based on CentOS6
>>"power outage"-save as possible. The hardware will be
>>switch off by pulling the plug.
>>
>>To accomplishing this goal, I would mounting some fs parts
>>readonly (e.g. /usr) and thinking about tmpfs for volatile
>>parts (e.g. lock, run under var). Additionally "optimize"
>>some vm.dirty_* kernel- and fs/ext4 parameters. /persistent
>>would be used with jffs2 on a CF card. So far the theory.
>>
>>Does anyone have some experience with such type of systems?
>>Any pointer to pitfalls are welcome.
>>

>Put it on a UPS, and install apcupsd.

Sure, for servers but I am talking about a small
9W-power-consumption appliance that have this
requirement:-)


I don't think CentOS is the appropriate distribution for that sort of 
system.   Does it even have jffs2 support?


a uClinux/busybox based system would be much more appropriate. maybe 
start with DSL, http://www.damnsmalllinux.org/ or tinycore, 
http://tinycorelinux.net/









--
john r pierce  37N 122W
somewhere on the middle of the left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[Leon Fauster]

Am 30.09.2014 um 19:08 schrieb m.r...@5-cent.us:
> Leon Fauster wrote:
>> I would like to setup a small system based on CentOS6
>> "power outage"-save as possible. The hardware will be
>> switch off by pulling the plug.
>> 
>> To accomplishing this goal, I would mounting some fs parts
>> readonly (e.g. /usr) and thinking about tmpfs for volatile
>> parts (e.g. lock, run under var). Additionally "optimize"
>> some vm.dirty_* kernel- and fs/ext4 parameters. /persistent
>> would be used with jffs2 on a CF card. So far the theory.
>> 
>> Does anyone have some experience with such type of systems?
>> Any pointer to pitfalls are welcome.
>> 
> Put it on a UPS, and install apcupsd.

Sure, for servers but I am talking about a small 
9W-power-consumption appliance that have this 
requirement :-)

--
LF


___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[John R Pierce]

On 9/30/2014 11:52 AM, Valeri Galtsev wrote:

I was thinking more in line of what apcupsd does: it runs as a daemon,
talks to UPS (and puts wall message about events like power loss...), and
executes command to cleanly shut down the box if less than (whatever % of
battery juice you configured to start clean shutdown at), and will issue
command to cancel shutdown if power returned after shutdown started
(sometimes you can do it...). And I usually don't need to do any
configuration (using GUI or command line utility) of the UPS itself... so
after initial configuration of apcupsd I never get back to it. And, BTW,
if you have half of a rack behind one UPS, you can set apcupsd on one
machine to talk to UPS, and on other machines set apcupsd to talk to
apcupsd on "master" machine making all of them aware, and act as
necessary.


nut and upsmon do exactly this.


--
john r pierce  37N 122W
somewhere on the middle of the left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[Valeri Galtsev]

On Tue, September 30, 2014 1:23 pm, John R Pierce wrote:
> On 9/30/2014 11:06 AM, Valeri Galtsev wrote:
>> Is there anything similar to apcupsd for that (preferably open source)?
>> (I
>> do remember ferrups...
>
> they have a whole GUI power management package that runs on linux but I
> tend to use the more basic shell-only stuff.  most of the Eatons I've
> used have had ethernet, they have a web interface on the UPS to
> configure, you can list dozens of systems the UPS can lob status updates
> at, and use it with nut [Network UPS Tools, available from epel] or
> whatever...   nut works with serial port and UPS based UPS's too.
>

I was thinking more in line of what apcupsd does: it runs as a daemon,
talks to UPS (and puts wall message about events like power loss...), and
executes command to cleanly shut down the box if less than (whatever % of
battery juice you configured to start clean shutdown at), and will issue
command to cancel shutdown if power returned after shutdown started
(sometimes you can do it...). And I usually don't need to do any
configuration (using GUI or command line utility) of the UPS itself... so
after initial configuration of apcupsd I never get back to it. And, BTW,
if you have half of a rack behind one UPS, you can set apcupsd on one
machine to talk to UPS, and on other machines set apcupsd to talk to
apcupsd on "master" machine making all of them aware, and act as
necessary.

Valeri


Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[m . roth]

John R Pierce wrote:
> On 9/30/2014 11:22 AM, m.r...@5-cent.us wrote:
>> The SmartUPS are... but then, overwhelmingly, mine are rackmount. I have
>> mentioned here, before, though, that at least with the SmartUPS, you can
>> easily, and far less expensively, buy replacement batteries, but they
>> *MUST*  be HR (high rate) batteries; anything else, and the SmartUPS
>> don't believe they've been replaced correctly.
>
> quality VRLA (SLA, AGM) batteries are capable of delivering massive
> current loads, I've not had any problems using these on good UPSs.At
> home, i've got an /ancient/ SmartUPS2000 (2KVA) tower unit that I
> repopulated with Panasonic 12V 20AH 'motorcycle' batteries.its been
> running great now for nearly 10 years, and STILL can keep my entire home
> computer load going for 4+ hours in a failure.These batteries are
> WAY past the 'normal' end of life, but are still doing very strong.   I
> even put a safety light on them, a floor lamp with a 7W LED bulb bounced
> off the ceiling, thats left always-on, as this room is quite dark.

Right... at home. I'm running mostly SmartUPS 3000s, rack mount, that take
eight batteries (which I can buy for about $100), or I could buy a new
set, with sled, for way over $300 The HRs should work in anything...
but I've got some of the 3000's that peak at over 90% usage (say, 3
64-core servers running flat out with a load over 70), and these batteries
allege, at that kind of load, < 15 min, maybe < 7. With the daily (or
twice daily - wonderful line we have here at a huge, major US gov't agency
in the DC 'burbs), it's fine, and they don't notice the second or two
blips.

mark

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[John R Pierce]

On 9/30/2014 11:22 AM, m.r...@5-cent.us wrote:

The SmartUPS are... but then, overwhelmingly, mine are rackmount. I have
mentioned here, before, though, that at least with the SmartUPS, you can
easily, and far less expensively, buy replacement batteries, but they
*MUST*  be HR (high rate) batteries; anything else, and the SmartUPS don't
believe they've been replaced correctly.


quality VRLA (SLA, AGM) batteries are capable of delivering massive 
current loads, I've not had any problems using these on good UPSs.At 
home, i've got an /ancient/ SmartUPS2000 (2KVA) tower unit that I 
repopulated with Panasonic 12V 20AH 'motorcycle' batteries.its been 
running great now for nearly 10 years, and STILL can keep my entire home 
computer load going for 4+ hours in a failure.These batteries are 
WAY past the 'normal' end of life, but are still doing very strong.   I 
even put a safety light on them, a floor lamp with a 7W LED bulb bounced 
off the ceiling, thats left always-on, as this room is quite dark.


--
john r pierce  37N 122W
somewhere on the middle of the left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[John R Pierce]

On 9/30/2014 11:06 AM, Valeri Galtsev wrote:

Is there anything similar to apcupsd for that (preferably open source)? (I
do remember ferrups...


they have a whole GUI power management package that runs on linux but I 
tend to use the more basic shell-only stuff.  most of the Eatons I've 
used have had ethernet, they have a web interface on the UPS to 
configure, you can list dozens of systems the UPS can lob status updates 
at, and use it with nut [Network UPS Tools, available from epel] or 
whatever...   nut works with serial port and UPS based UPS's too.







--
john r pierce  37N 122W
somewhere on the middle of the left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[m . roth]

John R Pierce wrote:
> On 9/30/2014 10:28 AM, Valeri Galtsev wrote:
>> And APC is the best in my experience. (Of course, there will be a couple
>> of brands with hardware  on the same level...)
>
> actually, I'd take an Eaton Powerware (formerly Best Power) over a APC
> any day.
>
> APC BackUPS grade stuff is strictly cheap consumer gear, I've had dozens
> of them fail over the years, all different BU models, the battery fails,
> you put a new battery in and the UPS still won't work. They
> consistently overcharge the batteries so they die in 2-3 years, when
> they should last 5+.
>
> The APC SmartUPS stuff is significantly better, but also a lot more
> expensive.

I think I may have an Eaton, or Compupower, at home. I think most of the
consumer-grade ones are similar.

The SmartUPS are... but then, overwhelmingly, mine are rackmount. I have
mentioned here, before, though, that at least with the SmartUPS, you can
easily, and far less expensively, buy replacement batteries, but they
*MUST* be HR (high rate) batteries; anything else, and the SmartUPS don't
believe they've been replaced correctly.

Isn't even a price difference - it's just for a different market, and most
of the vendors, nor the OEM's reps I've spoken to, know *anything* about
this.

mark

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[Valeri Galtsev]

On Tue, September 30, 2014 12:50 pm, John R Pierce wrote:
> On 9/30/2014 10:28 AM, Valeri Galtsev wrote:
>> And APC is the best in
>> my experience. (Of course, there will be a couple of brands with
>> hardware
>> on the same level...)
>
> actually, I'd take an Eaton Powerware (formerly Best Power) over a APC
> any day.

Is there anything similar to apcupsd for that (preferably open source)? (I
do remember ferrups... ;-)

>
> APC BackUPS grade stuff is strictly cheap consumer gear, I've had dozens
> of them fail over the years, all different BU models, the battery fails,
> you put a new battery in and the UPS still won't work. They
> consistently overcharge the batteries so they die in 2-3 years, when
> they should last 5+.
>
> The APC SmartUPS stuff is significantly better, but also a lot more
> expensive.
>

Indeed, I do stick to SmartUPS ... I should have mentioned it. Thanks,
John for weighing in !

Valeri


Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[John R Pierce]

On 9/30/2014 10:28 AM, Valeri Galtsev wrote:

And APC is the best in
my experience. (Of course, there will be a couple of brands with hardware
on the same level...)


actually, I'd take an Eaton Powerware (formerly Best Power) over a APC 
any day.


APC BackUPS grade stuff is strictly cheap consumer gear, I've had dozens 
of them fail over the years, all different BU models, the battery fails, 
you put a new battery in and the UPS still won't work. They 
consistently overcharge the batteries so they die in 2-3 years, when 
they should last 5+.


The APC SmartUPS stuff is significantly better, but also a lot more 
expensive.




--
john r pierce  37N 122W
somewhere on the middle of the left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[Valeri Galtsev]

On Tue, September 30, 2014 12:08 pm, m.r...@5-cent.us wrote:
> Leon Fauster wrote:
>> I would like to setup a small system based on CentOS6
>> "power outage"-save as possible. The hardware will be
>> switch off by pulling the plug.
>>
>> To accomplishing this goal, I would mounting some fs parts
>> readonly (e.g. /usr) and thinking about tmpfs for volatile
>> parts (e.g. lock, run under var). Additionally "optimize"
>> some vm.dirty_* kernel- and fs/ext4 parameters. /persistent
>> would be used with jffs2 on a CF card. So far the theory.
>>
>> Does anyone have some experience with such type of systems?
>> Any pointer to pitfalls are welcome.
>>
> Put it on a UPS, and install apcupsd.
>

I would say almost the same: put it behind _APC_ UPS, and install apcupsd.
As apcupsd will is designed to talk to APC made UPSes. It may talk nicely
to other brands, but I myself do not take chances. And APC is the best in
my experience. (Of course, there will be a couple of brands with hardware
on the same level...)

Valeri


Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] "power outage"-save / like embedded systems

[m . roth]

Leon Fauster wrote:
> I would like to setup a small system based on CentOS6
> "power outage"-save as possible. The hardware will be
> switch off by pulling the plug.
>
> To accomplishing this goal, I would mounting some fs parts
> readonly (e.g. /usr) and thinking about tmpfs for volatile
> parts (e.g. lock, run under var). Additionally "optimize"
> some vm.dirty_* kernel- and fs/ext4 parameters. /persistent
> would be used with jffs2 on a CF card. So far the theory.
>
> Does anyone have some experience with such type of systems?
> Any pointer to pitfalls are welcome.
>
Put it on a UPS, and install apcupsd.

  mark

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Lamar Owen]

On Thursday, July 07, 2011 12:05:30 PM Ljubomir Ljubojevic wrote:
> Well, it is not viable to run PC of the batteries (for long), but 
> hooking it up directly to the battery of the UPS (so UPS charges that 
> battery) is what I intend to do (There is nowhere to purchase them in my 
> country yet :-( ).

Looking at the way the picoPSU implements the +12V output, it should be 
possible to use the lm_sensors package in CentOS, or the motherboard 
manufacturer's utility (like SuperoDoctor for Supermicro motherboards) and get 
an alarm and an orderly shutdown based on the +12V line's voltage.  Could be an 
interesting application

But until you can get one.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Lamar Owen wrote:
> On Wednesday, July 06, 2011 05:23:36 PM John R Pierce wrote:
>> On 07/06/11 2:07 PM, Ljubomir Ljubojevic wrote:
>>> This part of the thread is about DC input ATX power supplies, 
> 
>> ah.  thats not what is commonly referred to as 'the ATX connector', so I 
>> was confused.
> 
> If you looked at the power supply Ljubomir previously linked to in the thread 
> (not the PowerStream unit, but the picoPSU one), you'd see that that 
> particular DC input power supply is built on the ATX connector itself and has 
> no separate mechanical case.  And gets 160W output power; which is excellent, 
> for an 'on-connector' power supply.  The whole supply is not much larger than 
> the ATX connector itself; seriously, go look at this little gem.
> 
> At that point you could put a 12V power supply and a sealed lead-acid battery 
> inside the PC case where the PSU normally goes. you'd just have to make 
> sure you add a schottky diode in series, since this picoPSU requires 
> regulated 12VDC input and has overvoltage protection set around 13.0 to 13.5 
> volts (lead acid float voltage 13.8 typical).  A 13.5 volt dry cell string 
> and a 13.5 volt regulated power supply with a pair of 1.5V drop power diodes 
> preventing the dry cells from charging would also work, and that sort of 
> arrangement would indeed be a 'torch' battery (common usage here is 
> 'flashlight' rather than 'torch') and that would fit the needs of the OP.
> 
> The PowerStream unit can work with unregulated 9-18 volts input, and would be 
> more suited to raw battery input.  Again, a diode isolator (similar to an 
> automotive accessory battery isolator diode set) would be required if 
> non-rechargeable batteries were to be used as the backup.
> 
> Speaking of, I actually have some old Mirapoint rackmounts, running CentOS of 
> course, that have built-in UPS's and redundant PSU's; haven't been able to 
> figure out whose UPS so that I could use them with apcupsd.

Well, it is not viable to run PC of the batteries (for long), but 
hooking it up directly to the battery of the UPS (so UPS charges that 
battery) is what I intend to do (There is nowhere to purchase them in my 
country yet :-( ).

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Always Learning]

On Wed, 2011-07-06 at 11:23 +0200, Ljubomir Ljubojevic wrote:

> There are smaller and cheaper 12V solutions Like the picoPSU's:
> http://www.mini-box.com/picoPSU-160-XT


Impressive. Thanks. 

Just need a 12v something to work the screen :-)

-- 
With best regards,

Paul.
England,
EU.

1 June 2010 Exclusively Centos & Gnome - Liberated from M$ Windoze. 


___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Lamar Owen]

On Wednesday, July 06, 2011 05:23:36 PM John R Pierce wrote:
> On 07/06/11 2:07 PM, Ljubomir Ljubojevic wrote:
> > This part of the thread is about DC input ATX power supplies, 

> ah.  thats not what is commonly referred to as 'the ATX connector', so I 
> was confused.

If you looked at the power supply Ljubomir previously linked to in the thread 
(not the PowerStream unit, but the picoPSU one), you'd see that that particular 
DC input power supply is built on the ATX connector itself and has no separate 
mechanical case.  And gets 160W output power; which is excellent, for an 
'on-connector' power supply.  The whole supply is not much larger than the ATX 
connector itself; seriously, go look at this little gem.

At that point you could put a 12V power supply and a sealed lead-acid battery 
inside the PC case where the PSU normally goes. you'd just have to make 
sure you add a schottky diode in series, since this picoPSU requires regulated 
12VDC input and has overvoltage protection set around 13.0 to 13.5 volts (lead 
acid float voltage 13.8 typical).  A 13.5 volt dry cell string and a 13.5 volt 
regulated power supply with a pair of 1.5V drop power diodes preventing the dry 
cells from charging would also work, and that sort of arrangement would indeed 
be a 'torch' battery (common usage here is 'flashlight' rather than 
'torch') and that would fit the needs of the OP.

The PowerStream unit can work with unregulated 9-18 volts input, and would be 
more suited to raw battery input.  Again, a diode isolator (similar to an 
automotive accessory battery isolator diode set) would be required if 
non-rechargeable batteries were to be used as the backup.

Speaking of, I actually have some old Mirapoint rackmounts, running CentOS of 
course, that have built-in UPS's and redundant PSU's; haven't been able to 
figure out whose UPS so that I could use them with apcupsd.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/06/11 2:07 PM, Ljubomir Ljubojevic wrote:
> This part of the thread is about DC input ATX power supplies, and I was
> referring to 12V input ATX power supply and the length of the cable
> between 12V source and 12V input PSU. "Direct" was meant to mean
> dirrectly from battery of the UPS to DC input PSU where UPS is next to
> the motherboard/case.

ah.  thats not what is commonly referred to as 'the ATX connector', so I 
was confused.


-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

John R Pierce wrote:
> On 07/06/11 1:41 PM, Ljubomir Ljubojevic wrote:
>> I would/will only use 12V power for direct connection from UPS battery
>> to ATX connector. It reduces conversion losses and power draw.
> 
> if by ATX connector, you mean the one on the motherboard, a standard ATX 
> mainboard requires REGULATED 12 volts, as well as 5V and 3.3V and 
> -5(legacy) and -12(legacy).  Your 12V battery is more like 14V when its 
> fully charged and connected to a trickle charger, and down around 11.5V 
> when its under load and mostly depleted.If you wanted to run a 
> mainboard on this sort of power, you would need a specially designed 
> mainboard with built in DC-DC supplies, or you would need a DC-DC 
> multi-voltage ATX compatible power supply (such as previously mentioned 
> on this thread)
> 
> 
This part of the thread is about DC input ATX power supplies, and I was 
referring to 12V input ATX power supply and the length of the cable 
between 12V source and 12V input PSU. "Direct" was meant to mean 
dirrectly from battery of the UPS to DC input PSU where UPS is next to 
the motherboard/case.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/06/11 1:41 PM, Ljubomir Ljubojevic wrote:
> I would/will only use 12V power for direct connection from UPS battery
> to ATX connector. It reduces conversion losses and power draw.

if by ATX connector, you mean the one on the motherboard, a standard ATX 
mainboard requires REGULATED 12 volts, as well as 5V and 3.3V and 
-5(legacy) and -12(legacy).  Your 12V battery is more like 14V when its 
fully charged and connected to a trickle charger, and down around 11.5V 
when its under load and mostly depleted.If you wanted to run a 
mainboard on this sort of power, you would need a specially designed 
mainboard with built in DC-DC supplies, or you would need a DC-DC 
multi-voltage ATX compatible power supply (such as previously mentioned 
on this thread)


-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Timothy Murphy wrote:
> Ljubomir Ljubojevic wrote:
> 
 Hook up ethernet, if its not POE, you plug it in, attach all the various
 usb cables, vga, serial, ps/2, ect ect to the server and let it hang.
 When your server is unresponsive just go ahead and hit the IP you
 assigned to your Spider, and you get a full console, virtual media, mass
 storage emulation, and the ability to mount samba shares and what not
 into it.
> How exactly would that work?
>>> I'm still not clear on this solution.
>>> Assuming you are actually doing this, could you tell me how you set it up
>>> in a little more detail, please.
>>>
>> You hook up device to the PC, and both to internet, device with public
>> IP, best if it is static, or with dynamic domain.
> 
> I'm not sure how I would connect both Spider and PC to the internet.
> If I had to purchase a second IP address,
> and pay my ISP for a second line,
> with the cost of the Spider this would be getting quite expensive.
> Maybe I have misunderstood something, as I am no network guru.
> 
You said your server is not directly on the internet, so I guess you 
have some sort of the router/firewall. On the router, direct (DNAT) 
needed ports to KVM and the rest to the Server.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

John R Pierce wrote:
> On 07/06/11 5:44 AM, Lamar Owen wrote:
>> Sure; we have a couple of small units like that for some solar-powered 
>> things we're doing here; however, the max I've seen for those plug-in type 
>> small ATX/ITX power supplies has been in the ~200W range (the specific one 
>> you linked to is only 160W), and my reply was specifically directed at the 
>> idea that lower than 48 VDC input was limited in power handling..  
>> PowerStream has a 500W 12VDC input unit, which is quite a bit more power 
>> than I've seen in the mini-ITX plugin supply categories.
> 
> 500 watts at 12VDC is 41 amps.   that requires some hefty wiring, and if 
> you have to run it any distances, either the wire is ridiculously heavy 
> (and expensive) or you suffer from voltage drop under load.
> 
> 500 watts at 120V is only 4 amps, and can easily be run 100s of feet 
> through simple lamp cord sized wiring.
> 
I would/will only use 12V power for direct connection from UPS battery 
to ATX connector. It reduces conversion losses and power draw.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Ljubomir Ljubojevic wrote:

>>> Hook up ethernet, if its not POE, you plug it in, attach all the various
>>> usb cables, vga, serial, ps/2, ect ect to the server and let it hang.
>>> When your server is unresponsive just go ahead and hit the IP you
>>> assigned to your Spider, and you get a full console, virtual media, mass
>>> storage emulation, and the ability to mount samba shares and what not
>>> into it.
>> 
 How exactly would that work?
>> 
>> I'm still not clear on this solution.
>> Assuming you are actually doing this, could you tell me how you set it up
>> in a little more detail, please.
>> 
> 
> You hook up device to the PC, and both to internet, device with public
> IP, best if it is static, or with dynamic domain.

I'm not sure how I would connect both Spider and PC to the internet.
If I had to purchase a second IP address,
and pay my ISP for a second line,
with the cost of the Spider this would be getting quite expensive.
Maybe I have misunderstood something, as I am no network guru.

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Keith Roberts]

On Wed, 6 Jul 2011, John R Pierce wrote:

> To: centos@centos.org
> From: John R Pierce 
> Subject: Re: [CentOS] Power-outage
> 
> On 07/06/11 5:44 AM, Lamar Owen wrote:
>> Sure; we have a couple of small units like that for some solar-powered 
>> things we're doing here; however, the max I've seen for those plug-in type 
>> small ATX/ITX power supplies has been in the ~200W range (the specific one 
>> you linked to is only 160W), and my reply was specifically directed at the 
>> idea that lower than 48 VDC input was limited in power handling..  
>> PowerStream has a 500W 12VDC input unit, which is quite a bit more power 
>> than I've seen in the mini-ITX plugin supply categories.
>
> 500 watts at 12VDC is 41 amps.   that requires some hefty wiring, and if
> you have to run it any distances, either the wire is ridiculously heavy
> (and expensive) or you suffer from voltage drop under load.
>
> 500 watts at 120V is only 4 amps, and can easily be run 100s of feet
> through simple lamp cord sized wiring.

That's why the mains distribution networks use a very high 
AC voltage at a lower amperage. That takes care of the 
voltage drop across over long distances, and reduces the 
need for higher amperage cables.

http://en.wikipedia.org/wiki/Electric_power_distribution

Kind Regards,

Keith Roberts

-
Websites:
http://www.karsites.net
http://www.php-debuggers.net
http://www.raised-from-the-dead.org.uk

All email addresses are challenge-response protected with
TMDA [http://tmda.net]
-
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Lamar Owen]

On Wednesday, July 06, 2011 12:24:12 PM John R Pierce wrote:
> 500 watts at 12VDC is 41 amps.   that requires some hefty wiring, and if 
> you have to run it any distances, either the wire is ridiculously heavy 
> (and expensive) or you suffer from voltage drop under load.

While not CentOS-specific, this *is* in my area of expertise.  We have 540Ah of 
-48VDC driven by a pair of Lorain Flotrol 200A rectifiers for our telco 
equipment (including the Cisco 12008 and OSR7609 routers).  Our solar sites are 
mostly 24VDC with, again, 540Ah minimum at each site, with a few 12VDC systems 
with 75 to 300Ah at each site.  I've run enough 4/0 and larger flex cables, 
that's for sure. for 41 amps, up to 25 feet or so, relatively small 8AWG is 
sufficient.  That's smaller gauge than the 6AWG and 4AWG I ran for the 12008 
and 7609, respectively, for -48VDC power.  (I say relatively small; the largest 
conductor size we have here is 6kA rated busbar, so even 2AWG or 2/0 AWG is 
relatively small..:-)   )  

I've seen much larger, specifically in the Brookhaven 5ESS in Atlanta.  I 
remember seeing one branch circuit idling at ~2.5kA.  Hmmm, speaking of 5ESS, I 
wonder what the chance of a CentOS for a 3B15 or 3B20 would be?   :-) (No, 
Russ, before you ask: I don't still have the 3B15's that used to be here.)

For a reference on DC power design, useful if you need to support CentOS 
servers with DC supplies in a telco environment, please see "DC Power System 
Design for Telecommunications" by Whitham D. Reeve for the 'canonical' 
reference work.  Everything you need, including current limit and overcurrent 
protection, low-voltage cutouts, distribution design, voltage drop and wire 
sizing calculations, and ampacity tables for DC (NEC includes AC ampacity 
tables, but not DC).

And I have a few CentOS boxes running on DC power.  And, of course, having 
powertop running on CentOS, and having some low-power modes, helps tremendously.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Rudi Ahlers]

On Wed, Jul 6, 2011 at 6:24 PM, John R Pierce  wrote:
> On 07/06/11 5:44 AM, Lamar Owen wrote:
>> Sure; we have a couple of small units like that for some solar-powered 
>> things we're doing here; however, the max I've seen for those plug-in type 
>> small ATX/ITX power supplies has been in the ~200W range (the specific one 
>> you linked to is only 160W), and my reply was specifically directed at the 
>> idea that lower than 48 VDC input was limited in power handling..  
>> PowerStream has a 500W 12VDC input unit, which is quite a bit more power 
>> than I've seen in the mini-ITX plugin supply categories.
>
> 500 watts at 12VDC is 41 amps.   that requires some hefty wiring, and if
> you have to run it any distances, either the wire is ridiculously heavy
> (and expensive) or you suffer from voltage drop under load.
>
> 500 watts at 120V is only 4 amps, and can easily be run 100s of feet
> through simple lamp cord sized wiring.
>
> --
> john r pierce                            N 37, W 122
> santa cruz ca                         mid-left coast
>
> ___
>


Which is why it's generally better to use 48V for these kinds of applications :)



-- 
Kind Regards
Rudi Ahlers
SoftDux

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/06/11 5:44 AM, Lamar Owen wrote:
> Sure; we have a couple of small units like that for some solar-powered things 
> we're doing here; however, the max I've seen for those plug-in type small 
> ATX/ITX power supplies has been in the ~200W range (the specific one you 
> linked to is only 160W), and my reply was specifically directed at the idea 
> that lower than 48 VDC input was limited in power handling..  PowerStream 
> has a 500W 12VDC input unit, which is quite a bit more power than I've seen 
> in the mini-ITX plugin supply categories.

500 watts at 12VDC is 41 amps.   that requires some hefty wiring, and if 
you have to run it any distances, either the wire is ridiculously heavy 
(and expensive) or you suffer from voltage drop under load.

500 watts at 120V is only 4 amps, and can easily be run 100s of feet 
through simple lamp cord sized wiring.

-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Lamar Owen]

On Wednesday, July 06, 2011 05:23:32 AM Ljubomir Ljubojevic wrote:
> Lamar Owen wrote:
> > We have a number of their -48V input supplies in use.  No, the 500W version 
> > in 12V input is not cheap.
> 
> There are smaller and cheaper 12V solutions Like the picoPSU's:
> http://www.mini-box.com/picoPSU-160-XT

Sure; we have a couple of small units like that for some solar-powered things 
we're doing here; however, the max I've seen for those plug-in type small 
ATX/ITX power supplies has been in the ~200W range (the specific one you linked 
to is only 160W), and my reply was specifically directed at the idea that lower 
than 48 VDC input was limited in power handling..  PowerStream has a 500W 
12VDC input unit, which is quite a bit more power than I've seen in the 
mini-ITX plugin supply categories.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Lamar Owen wrote:
> On Saturday, July 02, 2011 09:00:54 AM Jason Pyeron wrote:
>> You will either need many different batteries for the different voltages 
>> (1.2,
>> 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not very 
>> powerful
>> until the 48V input variety)
> 
> A company called PowerStream produces DC input ATX supplies for 12V, 24V, and 
> 48V input, all with up to 500W of power.  The 12V input page is at 
> http://www.powerstream.com/DC-PC-12V.htm
> 
> We have a number of their -48V input supplies in use.  No, the 500W version 
> in 12V input is not cheap.

There are smaller and cheaper 12V solutions Like the picoPSU's:
http://www.mini-box.com/picoPSU-160-XT

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/6/11, Marko Vojinovic  wrote:
> By (b) I mean having computer graphics overlayed on top of real-world
> scenery  (like in Terminator or Robocop movies). I'm just saying that this 
> kind of
> overlay is impossible to achieve with a regular human eye, except with very
> bulky equipment hanging off your head 15 cm in front of your face.

Somehow it just doesn't seem impossible to me, unless we insist on a
certain form-factor for the glasses as opposed to the sole requirement
that the frontal portion should be relatively thin.

How about a glass with lenses that are formed by nano beam
splitter/mirrors with projection units on the side where the legs of
the glasses would be. Thus transferring the bulk from the front to the
sides which would be more wearable than a heavy weight hanging off the
nose. The overlay would be generated by the projection units which is
reflected into the eye via the front mirror/beamsplitter which would
also allow external light in, albeit at half strength but that would
be what "shades" do after all ;)
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Tuesday 05 July 2011 21:31:50 Bowie Bailey wrote:
> On 7/2/2011 7:34 PM, Marko Vojinovic wrote:
> > I could in principle imagine all that coming in the future, but the
> > "monitor == shades" thing is just only Fi with no Sci in it. A human eye
> > cannot focus properly on any object which is closer to the eye than 10-15
> > cm (depending on the eye quality), so there is absolutely no way one can
> > use shades or contact lenses or something similar as a monitor,
> > regardless of technological levels of any human or alien races (James
> > Bond notwithstanding). Unless of course one surgically adapts the eye
> > lense itself, in which case the person would not be able to see anything
> > else... ;-)
> 
> Hmm...something like this perhaps?
> 
> http://www.i-glassesstore.com/i-3d.html
> 
> Still a bit bulky and expensive, but not impossible.  These apparently
> use a lens of some sort to allow the eye to focus at 5' while wearing
> them.  I had the chance to play with a pair of these 10 years ago.  At
> that time, the resolution sucked and they were about 1.5" thick.  They
> had built-in motion tracking.  Playing Descent with those things was a
> blast!  :)

Well, yes, sure, but they have to have this lens to allow the eye to focus 
properly, as you said. This means two crucial things: (a) they have to be 
bulky, and (b) there is no way to make them transparent, so that a person can 
watch the monitor picture and the outside world simultaneously.

By (b) I mean having computer graphics overlayed on top of real-world scenery 
(like in Terminator or Robocop movies). I'm just saying that this kind of 
overlay is impossible to achieve with a regular human eye, except with very 
bulky equipment hanging off your head 15 cm in front of your face.

Anyway, for both of the above reasons, these AV-headsets don't qualify even as 
a predecessor of "monitor-shades" (which are by assumption thin and 
transparent). These things are used for virtual reality applications, and they 
have existed for some time now. But as long as they cut you off from real 
world, I cannot consider them as "shades" in any way. ;-)

Best, :-)
Marko



___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Bowie Bailey]

On 7/2/2011 7:34 PM, Marko Vojinovic wrote:
>
> I could in principle imagine all that coming in the future, but the
> "monitor == shades" thing is just only Fi with no Sci in it. A human eye 
> cannot focus properly on any object which is closer to the eye than 10-15 cm 
> (depending on the eye quality), so there is absolutely no way one can use 
> shades or contact lenses or something similar as a monitor, regardless of 
> technological levels of any human or alien races (James Bond 
> notwithstanding). 
> Unless of course one surgically adapts the eye lense itself, in which case 
> the 
> person would not be able to see anything else... ;-)

Hmm...something like this perhaps?

http://www.i-glassesstore.com/i-3d.html

Still a bit bulky and expensive, but not impossible.  These apparently
use a lens of some sort to allow the eye to focus at 5' while wearing
them.  I had the chance to play with a pair of these 10 years ago.  At
that time, the resolution sucked and they were about 1.5" thick.  They
had built-in motion tracking.  Playing Descent with those things was a
blast!  :)

-- 
Bowie
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Lamar Owen]

On Saturday, July 02, 2011 09:00:54 AM Jason Pyeron wrote:
> You will either need many different batteries for the different voltages (1.2,
> 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not very powerful
> until the 48V input variety)

A company called PowerStream produces DC input ATX supplies for 12V, 24V, and 
48V input, all with up to 500W of power.  The 12V input page is at 
http://www.powerstream.com/DC-PC-12V.htm

We have a number of their -48V input supplies in use.  No, the 500W version in 
12V input is not cheap.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Timothy Murphy wrote:
> Steven Crothers wrote:
> 
>> Hook up ethernet, if its not POE, you plug it in, attach all the various
>> usb cables, vga, serial, ps/2, ect ect to the server and let it hang. When
>> your server is unresponsive just go ahead and hit the IP you assigned to
>> your Spider, and you get a full console, virtual media, mass storage
>> emulation, and the ability to mount samba shares and what not into it.
> 
>>> How exactly would that work?
> 
> I'm still not clear on this solution.
> Assuming you are actually doing this, could you tell me how you set it up
> in a little more detail, please.
> 

You hook up device to the PC, and both to internet, device with public 
IP, best if it is static, or with dynamic domain.

Then you use (app or web browser?) and open up IP of the device and you 
get somethink like VNC or TeamViewer but directly to hardware. Device 
has some sort of embedded OS in the firmware so you have access to all 
of your data, or at least I understood his comment in that way. Anyway, 
you can remotely even access BIOS screen.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Steven Crothers wrote:

> Hook up ethernet, if its not POE, you plug it in, attach all the various
> usb cables, vga, serial, ps/2, ect ect to the server and let it hang. When
> your server is unresponsive just go ahead and hit the IP you assigned to
> your Spider, and you get a full console, virtual media, mass storage
> emulation, and the ability to mount samba shares and what not into it.

>> How exactly would that work?

I'm still not clear on this solution.
Assuming you are actually doing this, could you tell me how you set it up
in a little more detail, please.

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R. Dennison]

On Tue, Jul 05, 2011 at 02:44:30PM +0800, Emmanuel Noobadmin wrote:

Can people at least pretend to keep this list on-topic?  89 responses
for an off-topic post is a little much, don't you think?

Item 3 under Guidelines as listed at:

http://www.centos.org/modules/tinycontent/index.php?id=16





John

-- 
This is all happening because my father didn't buy me a train set as a kid.

-- Warren Buffett, joking about his decision to buy a railroad, the Burlington
   Northern Santa Fe Corporation, New York Times, 4 November 2009


pgpsdfC1HqhB5.pgp
Description: PGP signature
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/04/11 11:44 PM, Emmanuel Noobadmin wrote:
> Otherwise, the single large UPS becomes the single point of failure.

the good big ones are fully redundant and every component is hot swappable.

but yeah, distributed UPS the way google did it is rather sweet.   As 
long as part of their operating plan is replacing every server by the 
time its batteries need replacing, they are good to go.You also need 
the sort of cloud management environment where your servers themselves 
are interchangable worker units and can be easily taken down for maintenance

OTOH, populating lots of racks with several APC SU3000's each is a pain 
in the butt.   Servicing dozens or 100s of per-rack UPS's when they are 
3-4 years old and need battery replacement is also very time consuming.  
a battery tray swap of a decent sized datacenter UPS takes a half day 
with a small fork lift.



-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/5/11, Rajagopal Swaminathan  wrote:
> 
> I was running a shop with two servers as ltsp with about 100 thin
> clients and a dozen projectors.
>
> One 20 KVA UPS powered all of them
>
> There was another 25KVS for critical fan light etc.
>
> Withing two years at least 20  (out of 64 IIRC) ("mainance free")
> batteries were replaced.

Fortunately I read about Google's server and their cheap per server
UPS approach and never went for the single high power UPS except when
absolutely needed. It was easier to deal with dead UPS in places where
there are more than one server simply by plugging the machine into the
other UPS while the first was replaced.

Otherwise, the single large UPS becomes the single point of failure.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Rajagopal Swaminathan]

Greetings,


On 7/5/11, Les Mikesell  wrote:
> On 7/4/11 5:14 PM, Timothy Murphy wrote:
>>
>   Generally replacing the battery will fix this, but by 6-10 years other
> components will go too.
>


I was running a shop with two servers as ltsp with about 100 thin
clients and a dozen projectors.

One 20 KVA UPS powered all of them

There was another 25KVS for critical fan light etc.

Withing two years at least 20  (out of 64 IIRC) ("mainance free")
batteries were replaced.

I insisted on water test on the batteries.

I would suggest do a water on test batteries _before_ buying/installing them

The entire battery pack was replaced. Thank god they were under
warranty. Otherwise I would have been skinless probably.

beware of maitenance free ones.

As the one man show , of course I will not mention the woe/sob/curses
Ihad to face due to outages. An oh almost all the users werere PHBs/
or would be PHBs


-- 
Regards,

Rajagopal
Mumbai, India
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Steven Crothers]

Hook up ethernet, if its not POE, you plug it in, attach all the various usb
cables, vga, serial, ps/2, ect ect to the server and let it hang. When your
server is unresponsive just go ahead and hit the IP you assigned to your
Spider, and you get a full console, virtual media, mass storage emulation,
and the ability to mount samba shares and what not into it.

On Sun, Jul 3, 2011 at 3:00 AM, Timothy Murphy  wrote:

> Steven Crothers wrote:
>
> > You should invest in a Spider KVM or similar, they hang off the back and
> > don't use any rack space. They can also be POE, so they wont use a plug.
> > That'll provide you out of band management and remote reboots and what
> > not.
>
> How exactly would that work?
>
> --
> Timothy Murphy
> e-mail: gayleard /at/ eircom.net
> tel: +353-86-2336090, +353-1-2842366
> s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland
>
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>



-- 
Steven Crothers
steven.croth...@gmail.com
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/04/11 3:40 PM, Les Mikesell wrote:
> One thing that might not have been mentioned yet: somewhere around three years
> out, a small UPS will cause an outage you wouldn't have otherwise when it 
> fails.
>Generally replacing the battery will fix this, but by 6-10 years other
> components will go too.

indeed, about half the times I've replaced the battery in a APC BackUPS 
or other low end UPS, the UPS itself was dead.

-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Les Mikesell]

On 7/4/11 5:14 PM, Timothy Murphy wrote:
>
> I've been completely convinced that a UPS is what I need,
> and am trying to source the APC UPS-BE350G, which was recommended.
>

One thing that might not have been mentioned yet: somewhere around three years 
out, a small UPS will cause an outage you wouldn't have otherwise when it 
fails. 
  Generally replacing the battery will fix this, but by 6-10 years other 
components will go too.

-- 
   Les Mikesell
lesmikes...@gmail.com
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Timothy Murphy wrote:
> I've been completely convinced that a UPS is what I need,
> and am trying to source the APC UPS-BE350G, which was recommended.

I used APC Back-UPS CS BK500EI in a company that I service and with 
their app (on Windows) I stretched lower and higher Volt boundary to 
something close to 165-240V (for 220V system) and they successfully 
stand cheaper emergency power generator when power goes out for a longer 
period of time.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Rudi Ahlers]

On Tue, Jul 5, 2011 at 12:14 AM, Timothy Murphy  wrote:

> John R Pierce wrote:
>
>
> Nb I didn't say, or mean to say, that I wanted to _make_ a "flashlight
> UPS".
> My electronic skill is close to zero.
>

Well, that's your first problem - not knowing how todo it :)



> I was simply expressing surprise that no-one had done it.
>

I have already done it. Years ago. In fact, my home server can run 2 hours
on batteries, and my ADSL modem + 24port GB switch can run about 14hours on
batteries.



>
> I've been completely convinced that a UPS is what I need,
> and am trying to source the APC UPS-BE350G, which was recommended.
>
>
In your case the UPS is the easiest route to follow



>
>
>
>
> --
>
>
-- 
Kind Regards
Rudi Ahlers
SoftDux

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

John R Pierce wrote:

> On 07/01/11 4:05 AM, Timothy Murphy wrote:
>> It seems to me that it should be possible
>> to have a simple, torch-battery operated
> 
> assuming 'torch' in this context means what us yank's call a flashlight,
> and that a 'torch battery' is a C or D cell, lets see how much juice we
> could get out of a reasonable setup..
> 
> According to HP's 'quick specs', the Microserver has a 150W supply, that
> nominally draws 0.63 A (from 115VAC) or 0.35 A rom 220VAC, about 75 watts.

In fact, my MicroServer has never exceeded 45 watts,
and usually runs at about 30 watts.
I'm not sure what sort of current a computer uses when shutting down?

> According to wikipedia, an alkaline D cell is typically rated at 1.2 amp
> hours at 1.5 volts.   Most inexpensive AC inverters run on 12V
> (automobile power), so we'd need 8 of them to get 1.2AH at 12V or about
> 14 watt*hours...   My calculations seem to suggest you'd get maybe 9
> minutes total from those 8 batteries with an 80% efficient AC inverter
> at 75 watts.   And then of course, you'd be throwing those 8 D cells
> away and replacing them with new ones.

Actually, I would only want the batteries to last long enough
to shut down the computer cleanly, which I think takes about 30 seconds.
And we can get quite large 12 volt batteries pretty cheaply
this side of the pond.

Nb I didn't say, or mean to say, that I wanted to _make_ a "flashlight UPS".
My electronic skill is close to zero.
I was simply expressing surprise that no-one had done it.

I've been completely convinced that a UPS is what I need,
and am trying to source the APC UPS-BE350G, which was recommended.





-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

James Matthews wrote:

> They have cheaper smaller UPS's that should be able to help you.

What UPS's are you suggesting?
(I didn't really follow your remark.)


-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[John R Pierce]

On 07/01/11 4:05 AM, Timothy Murphy wrote:
> It seems to me that it should be possible
> to have a simple, torch-battery operated

assuming 'torch' in this context means what us yank's call a flashlight, 
and that a 'torch battery' is a C or D cell, lets see how much juice we 
could get out of a reasonable setup..

According to HP's 'quick specs', the Microserver has a 150W supply, that 
nominally draws 0.63 A (from 115VAC) or 0.35 A rom 220VAC, about 75 watts.

According to wikipedia, an alkaline D cell is typically rated at 1.2 amp 
hours at 1.5 volts.   Most inexpensive AC inverters run on 12V 
(automobile power), so we'd need 8 of them to get 1.2AH at 12V or about 
14 watt*hours...   My calculations seem to suggest you'd get maybe 9 
minutes total from those 8 batteries with an 80% efficient AC inverter 
at 75 watts.   And then of course, you'd be throwing those 8 D cells 
away and replacing them with new ones.

NiCAD or NiMH rechargeable batteries aren't particularly suitable for 
this application, you'd need 10 of them as they are 1.2V, and they don't 
do well as standby power since they self discharge when idle for long 
periods.   UPS's almost always use lead-acid batteries as they are far 
more suitable for standby power applications.

A UPS is little more than a rechargeable battery, an A/C inverter 
circuit, a battery charger, and a controller for all that which also 
signals your computer when the power is failing.

-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[James Matthews]

They have cheaper smaller UPS's that should be able to help you.

On Fri, Jul 1, 2011 at 7:05 AM, Timothy Murphy  wrote:

> I have a CentOS-5.6 remote server in a house in Italy,
> where there are occasional thunder-storms.
>
> There was one yesterday, when the electricity
> went off 3 times, for a second or so on each occasion.
>
> My server, an HP MicroServer,
> came back (re-booted) on 2 of the 3 occasions,
> but not on the third.
>
> I assume that the problem arises because the machine
> does not close down properly.
> (Although it is also possible that a voltage surge
> might have been responsible -
> I have no surge protector on this supply.)
>
> It seems to me that it should be possible
> to have a simple, torch-battery operated, system
> which will keep the machine alive long enough
> to make a graceful exit.
> A full-blown UPS would be excessive, I think,
> as I only want the machine to re-boot
> when the current comes back on.
>
> I know there is a Remote Management (iLO) card
> for this machine, which might be useful for this.
> Unfortunately, I've already used the PCIe slot
> for a second ethernet card.
>
> Any advice or suggestions gratefully received.
>
> --
> Timothy Murphy
> e-mail: gayleard /at/ eircom.net
> tel: +353-86-2336090, +353-1-2842366
> s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland
>
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>



-- 
http://www.theboxery.com

--
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Sunday 03 July 2011 13:21:31 Robert Heller wrote:
> > Actually, now that I think more and more about it, I am not so sure it is
> > not doable. However, it is far from being trivial, and it certainly
> > cannot be something that can be as thin as ordinary shades. It has to be
> > bulky and heavy (due to the optics inside) and is bound to impair your
> > vision of the real world.
> > 
> > If I get some free time, I might even try to calculate the properties of
> > such a system of lenses, but I'm skeptic that the cool "monitor-shades"
> > will ever be possible. ;-)
> 
> OTOH, I would expect that people in the 1890's would consider the Apollo
> Moon landings as 'impossible'...  So, given enough advances in optics and
> monitor techology: LCD screens that can switch to complete
> transparency or to varying levels of transparency, and things like
> programmable lenses / optical systems, it becomes concievable.

Well, sure, but you have to make a very fine distinction between prejudices and 
facts, when it comes to making these sorts of predictions. I remember to have 
read somewhere that in 18th century it was widely believed that the human body 
cannot withstand velocities greater than 60 km/h, for whatever reason. But 
this was just due to the people's ignorance of the difference between velocity 
and acceleration. But when it comes to making claims about the optical 
properties of the human eye, no prejudices are involved --- it has been well 
explored and studied, and limits of what the eye can see (without artificial 
help) are a matter of fact, rather than unsupported opinion. ;-)

There is *no* *way* to have a plain eye read anything at 2 cm distance --- 
this is a fact, easily verifiable if you put your palm in front of your eye. 
Now, with some clever lenses and optics you might be able to trick the eye 
into thinking that the object is at a greater distance, and therefore 
circumvent this limitation. But having these optics constrained onto a width 
of typical shades is an *extreme* stretch, ultimately bounded by laws of 
physics. The laws of physics that apply here are already known, well-studied 
laws of geometric optics, and have to be obeyed regardless of any 
technological ingenuity. I haven't done any serious research, but I can say 
offhand that they provide very very little space for any hi-tech manouvers, no 
matter how advanced.

The more likely approach to what you want is to have some apparatus that 
dynamically measures the current width of the eye lens, and use a super-
tightly focused laser to draw the monitor picture directly on the eye retina. 
AFAIK, that is concievable, *provided* you can create a laser beam thin enough 
not to disperse drastically going through the eye lens, and thin enough to 
provide good "monitor resolution", and make it in appropriate color(s), and 
have low-enough power not to damage the retina on continuous exposure. By 
dynamically measuring the eye refraction properties, the device could in 
principle adjust the laser drawing to accomodate to the current position and 
the focus of the eye itself. The end result would be a person seeing glowing 
text "written" on the object that the eyes are currently looking at. When you 
look at something else, the device adjusts and you see the text written over a 
new object.

*If* you are technologically advanced enough to create a laser beam with such 
properties, this kind of a thing would be doable. Note, though, that the 
requrements of the beam being thin enough and low-enough in power may be in 
conflict with each other, and not satisfiable simultaneously (to be honest, I'm 
not sure without some digging into it, but at the very end you cannot 
circumvent Heisenberg's uncertainty principle, if all else can be done). But 
if that can be done, I can imagine a device like that to be constructed 
somehow.

Nevertheless, even then, this device would look like two lasers pointed into 
your eyes, and certainly *not* like cool shades. ;-)

Best, :-)
Marko

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Sun, 3 Jul 2011 04:30:37 +0100 CentOS mailing list  wrote:

> 
> On Sunday 03 July 2011 00:51:29 Robert Heller wrote:
> > > > There is (in the SciFi world) the idea that someday
> > > > 'desktops' in the current / conventional sense may completely vanish
> > > > from the universe, taken over progressably by laptops, tablets, smart
> > > > phones, wearable computers (motherboard == shirt, monitor == shades,
> > > > power supply == hat with embedded solar cells, virtual mouse/keyboard
> > > > via motion sensors in your shirt sleves/gloves, etc.),
> > > 
> > > I could in principle imagine all that coming in the future, but the
> > > "monitor == shades" thing is just only Fi with no Sci in it. A human eye
> > > cannot focus properly on any object which is closer to the eye than 10-15
> > > cm (depending on the eye quality), so there is absolutely no way one can
> > > use shades or contact lenses or something similar as a monitor,
> > > regardless of technological levels of any human or alien races (James
> > > Bond notwithstanding). Unless of course one surgically adapts the eye
> > > lense itself, in which case the person would not be able to see anything
> > > else... ;-)
> > 
> > Hmmm... There were a CS prof. and some students at UMass when I was
> > working there playing with a computer in a backpack with a 1" monitor
> > suspended from a head mount in front of one eye.  Not anything like
> > 10-15 cm.  If 10-15 cm is the minimum distance, what about telescope
> > eyepieces, camera viewfinders (including the little video ones on
> > camcorders), or binoculars? *I* know I can see images in the video
> > viewfinder of my Sony Hi8 camcorder just fine, with my right up close
> > (the old camcorder I have does NOT have a 3" swing out monitor). It is
> > all about the optics.
> 
> I wouldn't know about that CS prof. at UMass. Have any info that can point me 
> to him? Other examples you mention all have to do with lenses that twist the 
> trajectory of light to make distant or small things visible. When using 
> telescopes, binoculars, camera viewfinders, microscopes, and other stuff like 
> that, you are actually looking *through* a (transparent) device to see 
> something else outside, you're never looking *at* a device, or something that 
> is inside it.

I don't remember who was doing the experiements.

It would likely be a 1" camcorder viewfinder 'monitor', that is designed
to be right up against one's eye.

> 
> In contrast to that, actually drawing a picture which is 1-2cm away from the 
> eye is a completely different game. Just take a piece of paper, draw 
> something 
> on it and put it 2 cm in front of your eye. The drawing will get blurred. And 
> it's not because you used a thick pen, but because the eye lens cannot focus 
> on such a short distance.
> 
> Now, you might consider putting some convenient lenses between the paper and 
> the eye, to fix that problem. I don't have time do actually do the 
> calculation 
> of the properties of such a lens, but it's an interesting problem in 
> geometric 
> optics. You would want a convex lens that moves the focal point of the eye 
> from 15 cm to 2 cm. The trick is to find a transparent material which would 
> have a refraction index high enough that it can do what you want, while still 
> be thin enough to fit between the monitor and the eye (ie. it needs to be 
> thinner than 2 cm). I don't know if ordinary glass or any other material 
> would 
> do that or not. But it could be an interesting exercise for a student of 
> geometric optics. :-)
> 
> The bigger issue is the fact that, even if you manage to find an appropriate 
> lens to move the focal point to 2 cm, it is going to distort everything else 
> you see behind it. In principle you could devote one eye for the 
> monitor-only, 
> making the whole apparatus non-transparent, and use the other eye for the 
> outside world. That would, however, destroy the 3D vision of both the outside 
> world and eventual monitor 3D picture (because you can wear it only on one 
> eye).
> 
> Actually, now that I think more and more about it, I am not so sure it is not 
> doable. However, it is far from being trivial, and it certainly cannot be 
> something that can be as thin as ordinary shades. It has to be bulky and 
> heavy 
> (due to the optics inside) and is bound to impair your vision of the real 
> world.
> 
> If I get some free time, I might even try to calculate the properties of such 
> a system of lenses, but I'm skeptic that the cool "monitor-shades" will ever 
> be possible. ;-)

OTOH, I would expect that people in the 1890's would consider the Apollo
Moon landings as 'impossible'...  So, given enough advances in optics and
monitor techology: LCD screens that can switch to complete
transparency or to varying levels of transparency, and things like
programmable lenses / optical systems, it becomes concievable.

> 
> But now we are getting quite OT here... ;-)
> 
> Best, :-)
> Marko
> 
> _

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Ljubomir Ljubojevic wrote:
> Rajagopal Swaminathan wrote:
>> Greetings,,
>>
>> On 7/3/11, Robert Heller  wrote:
>>> At Sat, 2 Jul 2011 18:58:14 +0100 CentOS mailing list 
>>> wrote:
>>>  There is (in the SciFi world) the idea that someday
>>> 'desktops' in the current / conventional sense may completely vanish
>>> from the universe,
>> Something like this?:
>> http://www.youtube.com/watch?v=YrtANPtnhyg
>>
> Amassing technology synergy.
> 
> I liked even more his resolve to offer this as open source.
> 
> 
Hmmm, no open source for 3 years now. I might need to take my praise back.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Rajagopal Swaminathan wrote:
> Greetings,,
> 
> On 7/3/11, Robert Heller  wrote:
>> At Sat, 2 Jul 2011 18:58:14 +0100 CentOS mailing list 
>> wrote:
>>  There is (in the SciFi world) the idea that someday
>> 'desktops' in the current / conventional sense may completely vanish
>> from the universe,
> 
> Something like this?:
> http://www.youtube.com/watch?v=YrtANPtnhyg
> 
Amassing technology synergy.

I liked even more his resolve to offer this as open source.


Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/3/11, Les Mikesell  wrote:
> If you are facebook, you can design/demand whatever you want, including
> single-voltage motherboards.  Not sure why everyone else put up with the
> problem for so long.

Legacy support and pure economies of scale :D
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/3/11, Robert Heller  wrote:
> (I'm guessing that Google's massive array of battery powered servers use
> things like Atom processors or some other mobile or embeded processing
> elements on their custom motherboards, which might be a customized
> variant of a laptop or embedded processing motherboard.)

IIRC, Google's server boards run normal processors. It's just the
board was customized to work off single+12V  voltage, with a battery
sitting in between to act as a UPS. The reason was a single +12V
battery per server was cheaper than a huge UPS for a bunch of servers.
Google also use enough boards that it was economically feasible for
the manufacturer to make design changes to an existing board design to
support this.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/3/11, Marko Vojinovic  wrote:
> be a good investment, but still I wonder why there are no offers on the
> market with a "boosted" PSU units that can sustain DC power for a couple of 
> seconds
> during the AC "blinks". They don't even need to use a battery, maybe a set
> of  condensers could sustain power for a short period (although I might be
> wrong,  never did the numbers on that).

> Given that I believe there certainly is a market for such a PSU, I'm just
> surprised nobody is selling it yet. You cannot assume that the AC wall
> outlet  will always provide perfect power... ;-)

Ah, manufacturers do sell this stuff at least a few years back. It
came with a battery pack that was installed into the 5.25" drive bay.
But as this type never made it into mainstream awareness, likely due
to the low cost of a basic UPS nowadays, it just didn't make sense
when such a PSU cost almost the same as a normal PSU + UPS. And the
UPS had a longer run time as well as being able to support a few other
accessories at the same time, and acts as a shield by sitting between
any power surge and your PSU, as opposed to the PSU + battery.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Steven Crothers wrote:

> You should invest in a Spider KVM or similar, they hang off the back and
> don't use any rack space. They can also be POE, so they wont use a plug.
> That'll provide you out of band management and remote reboots and what
> not.

How exactly would that work?

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Steven Crothers]

You should invest in a Spider KVM or similar, they hang off the back and
don't use any rack space. They can also be POE, so they wont use a plug.
That'll provide you out of band management and remote reboots and what not.

On Fri, Jul 1, 2011 at 7:05 AM, Timothy Murphy  wrote:

> I have a CentOS-5.6 remote server in a house in Italy,
> where there are occasional thunder-storms.
>
> There was one yesterday, when the electricity
> went off 3 times, for a second or so on each occasion.
>
> My server, an HP MicroServer,
> came back (re-booted) on 2 of the 3 occasions,
> but not on the third.
>
> I assume that the problem arises because the machine
> does not close down properly.
> (Although it is also possible that a voltage surge
> might have been responsible -
> I have no surge protector on this supply.)
>
> It seems to me that it should be possible
> to have a simple, torch-battery operated, system
> which will keep the machine alive long enough
> to make a graceful exit.
> A full-blown UPS would be excessive, I think,
> as I only want the machine to re-boot
> when the current comes back on.
>
> I know there is a Remote Management (iLO) card
> for this machine, which might be useful for this.
> Unfortunately, I've already used the PCIe slot
> for a second ethernet card.
>
> Any advice or suggestions gratefully received.
>
> --
> Timothy Murphy
> e-mail: gayleard /at/ eircom.net
> tel: +353-86-2336090, +353-1-2842366
> s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland
>
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>



-- 
Steven Crothers
steven.croth...@gmail.com
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[夜神 岩男]

On Sat, 2011-07-02 at 03:03 +0800, Emmanuel Noobadmin wrote:
> On 7/1/11, Timothy Murphy  wrote:
> > It seems to me that it should be possible
> > to have a simple, torch-battery operated, system
> > which will keep the machine alive long enough
> > to make a graceful exit.
> > A full-blown UPS would be excessive, I think,
> > as I only want the machine to re-boot
> > when the current comes back on.
> 
> Like others have suggested, a cheap UPS is the way to go. The problem
> with your idea is that you'll need a DC to AC inverter that can handle
> the output current required by your server and something to hold the
> batteries (you'll need more than one because attempting to draw a huge
> current from a normal battery will either kill it or at the very least
> cause it to have a shorter than expected capacity) and everything
> together, it's probably going to cost more in both money and time to
> have this thing.

You will also need to have the device signal the OS to shutdown cleanly
and be set to reboot when the power comes back on.

And once you've added those features, you will have created a UPS --
likely at an expense in time/money that exceeds simply having bought
one. Specifically, a 300W UPS can be had for less than $40 -- that's
0.5~4 hours of overtime or side work depending on your job. You are
likely to expend a lot more than 4 hours putting your homemade solution
together and achieve a far less reliable result. Unless the experience
of amateur electrical engineering is what you are craving (it *is* fun)
buy a UPS and be done with it -- just read the docs so you fully
understand how to make it tell your computer to start shutting down or
booting up, etc. They aren't magic and require a little set up to be
fully utilized.


___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Drew]

>> Robert Heller suggested that UPS architecture matters:
>> AC->DC::DC Batteries::DC->AC
>> Where input AC is electrically decoupled from output AC.
>> Not many adverts for UPS's explain whether this is the case with their
>> UPS.
>>
>
> APC's SmartUPS line, Liebert, and Eaton Powerware are all true-sine wave 
> UPS's, and do proper decoupling. Unfortunately, this kind
> of data doesn't make for great ad copy, so it's left out, and you have to dig 
> deep into datasheets to get that information. I pretty
> much only use APC, and we have truly crap power here. Because of some heavy 
> industry in the area, brownouts are common, and that'll
> kill a PC power supply better than anything. I've pulled one 7 year old APC 
> from a server closet where the lightning took the top of
> the telephone pole OFF. THE UPS was fried, some of the breakers in the 
> building were fused (!), but the servers were fine, outside
> of the router that got zapped from the DSL modem.

I beg to differ about APC. The accepted term for what Robert described
is a "double conversion" or "online" UPS. APC's SmartUPS family is
only available with the double conversion feature if you specify a
"SmartUPS Online" model. The rest of the SmartUPS family use "Line
Interactive" which runs on mains power until the
voltage/current/frequency goes out of tolerance, at which point they
cut over to battery. The Liebert GXT2/3 family which we use quite a
bit of were, until recently, strictly double conversion.


-- 
Drew

"This started out as a hobby and spun horribly out of control."
-Unknown
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Sunday 03 July 2011 00:51:29 Robert Heller wrote:
> > > There is (in the SciFi world) the idea that someday
> > > 'desktops' in the current / conventional sense may completely vanish
> > > from the universe, taken over progressably by laptops, tablets, smart
> > > phones, wearable computers (motherboard == shirt, monitor == shades,
> > > power supply == hat with embedded solar cells, virtual mouse/keyboard
> > > via motion sensors in your shirt sleves/gloves, etc.),
> > 
> > I could in principle imagine all that coming in the future, but the
> > "monitor == shades" thing is just only Fi with no Sci in it. A human eye
> > cannot focus properly on any object which is closer to the eye than 10-15
> > cm (depending on the eye quality), so there is absolutely no way one can
> > use shades or contact lenses or something similar as a monitor,
> > regardless of technological levels of any human or alien races (James
> > Bond notwithstanding). Unless of course one surgically adapts the eye
> > lense itself, in which case the person would not be able to see anything
> > else... ;-)
> 
> Hmmm... There were a CS prof. and some students at UMass when I was
> working there playing with a computer in a backpack with a 1" monitor
> suspended from a head mount in front of one eye.  Not anything like
> 10-15 cm.  If 10-15 cm is the minimum distance, what about telescope
> eyepieces, camera viewfinders (including the little video ones on
> camcorders), or binoculars? *I* know I can see images in the video
> viewfinder of my Sony Hi8 camcorder just fine, with my right up close
> (the old camcorder I have does NOT have a 3" swing out monitor). It is
> all about the optics.

I wouldn't know about that CS prof. at UMass. Have any info that can point me 
to him? Other examples you mention all have to do with lenses that twist the 
trajectory of light to make distant or small things visible. When using 
telescopes, binoculars, camera viewfinders, microscopes, and other stuff like 
that, you are actually looking *through* a (transparent) device to see 
something else outside, you're never looking *at* a device, or something that 
is inside it.

In contrast to that, actually drawing a picture which is 1-2cm away from the 
eye is a completely different game. Just take a piece of paper, draw something 
on it and put it 2 cm in front of your eye. The drawing will get blurred. And 
it's not because you used a thick pen, but because the eye lens cannot focus 
on such a short distance.

Now, you might consider putting some convenient lenses between the paper and 
the eye, to fix that problem. I don't have time do actually do the calculation 
of the properties of such a lens, but it's an interesting problem in geometric 
optics. You would want a convex lens that moves the focal point of the eye 
from 15 cm to 2 cm. The trick is to find a transparent material which would 
have a refraction index high enough that it can do what you want, while still 
be thin enough to fit between the monitor and the eye (ie. it needs to be 
thinner than 2 cm). I don't know if ordinary glass or any other material would 
do that or not. But it could be an interesting exercise for a student of 
geometric optics. :-)

The bigger issue is the fact that, even if you manage to find an appropriate 
lens to move the focal point to 2 cm, it is going to distort everything else 
you see behind it. In principle you could devote one eye for the monitor-only, 
making the whole apparatus non-transparent, and use the other eye for the 
outside world. That would, however, destroy the 3D vision of both the outside 
world and eventual monitor 3D picture (because you can wear it only on one 
eye).

Actually, now that I think more and more about it, I am not so sure it is not 
doable. However, it is far from being trivial, and it certainly cannot be 
something that can be as thin as ordinary shades. It has to be bulky and heavy 
(due to the optics inside) and is bound to impair your vision of the real 
world.

If I get some free time, I might even try to calculate the properties of such 
a system of lenses, but I'm skeptic that the cool "monitor-shades" will ever 
be possible. ;-)

But now we are getting quite OT here... ;-)

Best, :-)
Marko

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Rajagopal Swaminathan]

Greetings,,

On 7/3/11, Robert Heller  wrote:
> At Sat, 2 Jul 2011 18:58:14 +0100 CentOS mailing list 
> wrote:
>  There is (in the SciFi world) the idea that someday
> 'desktops' in the current / conventional sense may completely vanish
> from the universe,

Something like this?:
http://www.youtube.com/watch?v=YrtANPtnhyg

-- 
Regards,

Rajagopal
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jason Pyeron]

> -Original Message-
> From: centos-boun...@centos.org 
> [mailto:centos-boun...@centos.org] On Behalf Of Devin Reade
> Sent: Saturday, July 02, 2011 15:51
> To: CentOS mailing list
> Subject: Re: [CentOS] Power-outage
> 
> Ljubomir Ljubojevic  wrote:
> 
> > First is to have LAN power controller/switch, can't 
> remember how you 
> > call it. It can monitor several inputs like voltage, 
> on/off, etc, and 
> > it can be used to cut and restore power, as well as reboot. 
> They have 
> > web interface and are accessible via IP. Wireless network 
> guys use them.
> 
> I do in fact use these (they're called managed power 
> distribution units, such as the APC AP7900), not only for 
> such manual operations but also because they're good for 
> doing fencing in HA clusters.
> 
> However, that does not alter the fact that this solution 
> requires human intervention (albiet in this case you can do 
> it remotely).
> It doesn't fix the flaw, it just works around it.

Our dhcp server can run for many days on battery, it has a script running that
if a machine does not ping, it sends a WOL. It does not do this if the network
AC is off. If the AC is resored for more than 30 minutes, the script resumes.
Machines wake up.

> 
> It's also an additional expense that I don't think would be 
> in the OP's scope.
> 


Also regarding DB taking too long to shut down, we use hibernation now. It is
fast.


-Jason 

--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-   -
- Jason Pyeron  PD Inc. http://www.pdinc.us -
- Principal Consultant  10 West 24th Street #100-
- +1 (443) 269-1555 x333Baltimore, Maryland 21218   -
-   -
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
This message is copyright PD Inc, subject to license 20080407P00.

 

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Sun, 3 Jul 2011 00:34:18 +0100 CentOS mailing list  wrote:

> 
> On Saturday 02 July 2011 21:13:59 Robert Heller wrote:
> > > I'm using an UPS for my desktop system, but I don't need it for the
> > > laptop. If the AC power drops, even for a moment, the laptop battery
> > > will kick in and sustain the machine. I just think that the same thing
> > > can be implemented for the desktop too. If I understood the OP
> > > correctly... ;-)
> > 
> > A laptop effectively contains its own UPS in the form of a power brick,
> > battery and power supply on its motherboard.
> > 
> > Yes, one *could* build a desktop or server that way, but why bother,
> > since AC wall outlets are everywhere one might want to use a desktop or
> > server?
> 
> Well, one reason I can think of is that one cannot always trust the AC wall 
> outlet to provide uninterrupted power? By that I don't mean AC power going 
> down for an hour, but for a fraction of a second.
> 
> I happen to live near an industrial zone, and every morning between 10 and 
> 11h 
> someone turns on something in the nearby factory, which makes my light-bulbs 
> blink twice. Of course, that's enough to reboot my desktop machine no 
> problem. 
> I had to buy an UPS system just because of that. Granted, an UPS turned out 
> to 
> be a good investment, but still I wonder why there are no offers on the 
> market 
> with a "boosted" PSU units that can sustain DC power for a couple of seconds 
> during the AC "blinks". They don't even need to use a battery, maybe a set of 
> condensers could sustain power for a short period (although I might be wrong, 
> never did the numbers on that).
> 
> A friend of mine lives near the Technical Sciences university (in the middle 
> of the city, they don't have a campus), where they have a medium-sized wind 
> tunnel for the aero-engineering courses. Every time they turn the thing on, 
> the whole city block loses power for cca 5 seconds. Sure, it's bad AC grid 
> design, but bad designs are usually a fact of life. :-)
> 
> I'm speculating here about an improved PSU device which would be more 
> expensive than the ordinary one, but less expensive than a typical UPS 
> system. 
> Given that I believe there certainly is a market for such a PSU, I'm just 
> surprised nobody is selling it yet. You cannot assume that the AC wall outlet 
> will always provide perfect power... ;-)
> 
> > There is (in the SciFi world) the idea that someday
> > 'desktops' in the current / conventional sense may completely vanish
> > from the universe, taken over progressably by laptops, tablets, smart
> > phones, wearable computers (motherboard == shirt, monitor == shades,
> > power supply == hat with embedded solar cells, virtual mouse/keyboard
> > via motion sensors in your shirt sleves/gloves, etc.),
> 
> I could in principle imagine all that coming in the future, but the
> "monitor == shades" thing is just only Fi with no Sci in it. A human eye 
> cannot focus properly on any object which is closer to the eye than 10-15 cm 
> (depending on the eye quality), so there is absolutely no way one can use 
> shades or contact lenses or something similar as a monitor, regardless of 
> technological levels of any human or alien races (James Bond 
> notwithstanding). 
> Unless of course one surgically adapts the eye lense itself, in which case 
> the 
> person would not be able to see anything else... ;-)

Hmmm... There were a CS prof. and some students at UMass when I was
working there playing with a computer in a backpack with a 1" monitor
suspended from a head mount in front of one eye.  Not anything like
10-15 cm.  If 10-15 cm is the minimum distance, what about telescope
eyepieces, camera viewfinders (including the little video ones on
camcorders), or binoculars? *I* know I can see images in the video
viewfinder of my Sony Hi8 camcorder just fine, with my right up close
(the old camcorder I have does NOT have a 3" swing out monitor). It is
all about the optics.


> 
> > or even
> > implanted computers (eg as a thin circuit board between your skull and
> > scalp, and 'wired' directly into your brain).
> 
> I would never wire a brain to a machine. Brains make errors, are susceptible 
> to emotions, hormons, vanity, etc., and just introduce a large point of 
> failure for the otherwise-correct machines. ;-)
> 
> > This seems to already be
> > happening to some extent, in that laptops are becoming the computer of
> > choise and desktops are becomming an 'old school' sort of thing.
> 
> Yeah, the laptops are becoming cheap enough, so that once your computing 
> needs 
> grow out of your current laptop, you don't even think of "upgrading" it, but 
> rather just buy a new model. Desktops will be in use only for custom things 
> (professionals who need, say, five audio cards in one machine) and small 
> servers. But we're getting sort-of OT here... ;-)
> 
> Best, :-)
> Marko
> 
> 
> ___
> CentOS mailing list
> CentOS@centos.or

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Saturday 02 July 2011 21:13:59 Robert Heller wrote:
> > I'm using an UPS for my desktop system, but I don't need it for the
> > laptop. If the AC power drops, even for a moment, the laptop battery
> > will kick in and sustain the machine. I just think that the same thing
> > can be implemented for the desktop too. If I understood the OP
> > correctly... ;-)
> 
> A laptop effectively contains its own UPS in the form of a power brick,
> battery and power supply on its motherboard.
> 
> Yes, one *could* build a desktop or server that way, but why bother,
> since AC wall outlets are everywhere one might want to use a desktop or
> server?

Well, one reason I can think of is that one cannot always trust the AC wall 
outlet to provide uninterrupted power? By that I don't mean AC power going 
down for an hour, but for a fraction of a second.

I happen to live near an industrial zone, and every morning between 10 and 11h 
someone turns on something in the nearby factory, which makes my light-bulbs 
blink twice. Of course, that's enough to reboot my desktop machine no problem. 
I had to buy an UPS system just because of that. Granted, an UPS turned out to 
be a good investment, but still I wonder why there are no offers on the market 
with a "boosted" PSU units that can sustain DC power for a couple of seconds 
during the AC "blinks". They don't even need to use a battery, maybe a set of 
condensers could sustain power for a short period (although I might be wrong, 
never did the numbers on that).

A friend of mine lives near the Technical Sciences university (in the middle 
of the city, they don't have a campus), where they have a medium-sized wind 
tunnel for the aero-engineering courses. Every time they turn the thing on, 
the whole city block loses power for cca 5 seconds. Sure, it's bad AC grid 
design, but bad designs are usually a fact of life. :-)

I'm speculating here about an improved PSU device which would be more 
expensive than the ordinary one, but less expensive than a typical UPS system. 
Given that I believe there certainly is a market for such a PSU, I'm just 
surprised nobody is selling it yet. You cannot assume that the AC wall outlet 
will always provide perfect power... ;-)

> There is (in the SciFi world) the idea that someday
> 'desktops' in the current / conventional sense may completely vanish
> from the universe, taken over progressably by laptops, tablets, smart
> phones, wearable computers (motherboard == shirt, monitor == shades,
> power supply == hat with embedded solar cells, virtual mouse/keyboard
> via motion sensors in your shirt sleves/gloves, etc.),

I could in principle imagine all that coming in the future, but the
"monitor == shades" thing is just only Fi with no Sci in it. A human eye 
cannot focus properly on any object which is closer to the eye than 10-15 cm 
(depending on the eye quality), so there is absolutely no way one can use 
shades or contact lenses or something similar as a monitor, regardless of 
technological levels of any human or alien races (James Bond notwithstanding). 
Unless of course one surgically adapts the eye lense itself, in which case the 
person would not be able to see anything else... ;-)

> or even
> implanted computers (eg as a thin circuit board between your skull and
> scalp, and 'wired' directly into your brain).

I would never wire a brain to a machine. Brains make errors, are susceptible 
to emotions, hormons, vanity, etc., and just introduce a large point of 
failure for the otherwise-correct machines. ;-)

> This seems to already be
> happening to some extent, in that laptops are becoming the computer of
> choise and desktops are becomming an 'old school' sort of thing.

Yeah, the laptops are becoming cheap enough, so that once your computing needs 
grow out of your current laptop, you don't even think of "upgrading" it, but 
rather just buy a new model. Desktops will be in use only for custom things 
(professionals who need, say, five audio cards in one machine) and small 
servers. But we're getting sort-of OT here... ;-)

Best, :-)
Marko


___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Sat, 2 Jul 2011 18:58:14 +0100 CentOS mailing list  wrote:

> 
> On Saturday 02 July 2011 18:21:27 Jason Pyeron wrote:
> > > > > But surely computers actually use DC, so couldn't my
> > > > > torch-battery
> > > > > device just supply the PC components directly?
> > > > 
> > > > A PC uses several *different* DC voltages: +12, +5, +3.3,
> > > > and several
> > > > others and they need to be *precise*.  Some of these are
> > > > not an exact
> > > > multiples of the standard 1.5V Carbon-Zinc cells typicaly used in
> > > > torch batteries.
> > > 
> > > I wonder, how is this issue solved in laptops? They use only
> > > one DC battery, typically with a single voltage output, AFAIK.
> > 
> > (sorry ctrl-enter sends...)
> > 
> > Laptops, google mother boards, etc have power supply circuits on board.
> > Remember that a switching powersupply taking AC still has dc to dc
> > converters in it after the conditioning stage.
> 
> So couldn't the OP then plug a battery "in between" (I'm talking in principle 
> here, not realistically) --- after the AC-to-DC stage but before the 
> "conditioning" stage?

The input DC side 'normal' switching power supply is like 100+ volts DC,
since it is just rectified and lightly filtered from the Mains.  And
short of completely tearing the PC's power supply apart and rebuilding
it, it is just not a trivial thing to do.

> 
> If a laptop can have several *different* and *precise* voltages from a single 
> DC battery, why the desktop cannot?

In theory it could, it just does not need to. The AC vs. DC mains war
was lost like 100 years ago.  ALL main 'wall' power is AC, either 110 or
220, 50 or 60hz.  Since desktops (and servers) are meant to be 'plugged
into the wall', the power supplies of all want 110VAC or 220VAC (or possible
either) at 50 or 60hz.

> 
> I am not saying that it would be easy or cheap, just that the above 
> "different 
> voltages" argument seems false from my POV. If a laptop can be battery-
> powered, so can a desktop (given that you have all the hardware to implement 
> it). You don't need to tweak the motherboard, just the PSU. It's routinely 
> done in laptops, so it doesn't seem to be rocket-science or something too 
> expensive. I wonder why aren't there any desktops on the market with same 
> technology?

The closest thing is a 'lunch box': a desktop system you can carry. 
Although once you get there, you just plug it into the nearest wall
outlet.  In all 'moving' situations, AC power is available: Amtrak
trains all have 110V outlets at every seat. I imagine passenger
aircraft also have 110V outlets ditto for ships at sea or even RVs (in
both cases, hanging an alternator onto the engine is a trivial task).
Building a battery powered *desktop* (or server) just does not make
sense, unless you are Google (or the Army, Airforce, Navy, or NASA) and
want servers that are imune to power failures, in which case you just
custom build what you need.

The different voltages argument is not the argument against a battery
powered desktop, just that a battery powered desktop (or server) is a
non-trivial design.  One cannot just solder a pair of wires onto the
motherboard and connect them to some random battery.  One has to start
with either a motherboard *designed* to be connected to a battery (eg
a laptop motherboard or Google custom server motherboard) OR a power
supply meant to be connected to a DC (eg battery) power source.  I
believe there do exist ATX power supplies that are meant to be connected to
a DC power source (like a battery).  I expect that the *military* might
use such in some situations.  

> 
> I'm using an UPS for my desktop system, but I don't need it for the laptop. 
> If 
> the AC power drops, even for a moment, the laptop battery will kick in and 
> sustain the machine. I just think that the same thing can be implemented for 
> the desktop too. If I understood the OP correctly... ;-)

A laptop effectively contains its own UPS in the form of a power brick,
battery and power supply on its motherboard.

Yes, one *could* build a desktop or server that way, but why bother,
since AC wall outlets are everywhere one might want to use a desktop or
server? Anyplace where a power outlet is not available, you use a
laptop. A laptop is a special class (as is a smart phone or a tablet)
of system.  There is (in the SciFi world) the idea that someday
'desktops' in the current / conventional sense may completely vanish
from the universe, taken over progressably by laptops, tablets, smart
phones, wearable computers (motherboard == shirt, monitor == shades,
power supply == hat with embedded solar cells, virtual mouse/keyboard
via motion sensors in your shirt sleves/gloves, etc.), or even
implanted computers (eg as a thin circuit board between your skull and
scalp, and 'wired' directly into your brain).  This seems to already be
happening to some extent, in that laptops are becoming the computer of
choise and desktops are becomming an 'old school' sort of thing.

> 
> 

Re: [CentOS] Power-outage

[Robert Heller]

At Sat, 2 Jul 2011 18:10:09 +0100 CentOS mailing list  wrote:

> 
> On Saturday 02 July 2011 15:45:11 Robert Heller wrote:
> > At Sat, 02 Jul 2011 14:52:27 +0200 CentOS mailing list  
> wrote:
> > > Emmanuel Noobadmin wrote:
> > > >> It seems to me that it should be possible
> > > >> to have a simple, torch-battery operated, system
> > > >> which will keep the machine alive long enough
> > > >> to make a graceful exit.
> > > > 
> > > > The problem
> > > > with your idea is that you'll need a DC to AC inverter that can handle
> > > > the output current required by your server and something to hold the
> > > > batteries (you'll need more than one because attempting to draw a huge
> > > > current from a normal battery will either kill it or at the very least
> > > > cause it to have a shorter than expected capacity) and everything
> > > > together, it's probably going to cost more in both money and time to
> > > > have this thing.
> > > 
> > > I'm sure you are right, as I know nothing at all about power supplies.
> > > But surely computers actually use DC,
> > > so couldn't my torch-battery device just supply the PC components
> > > directly?
> > 
> > A PC uses several *different* DC voltages: +12, +5, +3.3, and several
> > others and they need to be *precise*.  Some of these are not an exact
> > multiples of the standard 1.5V Carbon-Zinc cells typicaly used in torch
> > batteries.
> 
> I wonder, how is this issue solved in laptops? They use only one DC battery, 
> typically with a single voltage output, AFAIK.

*Mobile* processors don't use as many voltages.  You will note that
laptop disks use a single 5V for power, as opposed to the 5V (logic) and
12V (motor) power a desktop or server disk drive uses.

Laptops also use DC-DC power converters to get the addition *few*
volatages needed (eg 12 => 5V and 3.3V).

(I'm guessing that Google's massive array of battery powered servers use
things like Atom processors or some other mobile or embeded processing
elements on their custom motherboards, which might be a customized
variant of a laptop or embedded processing motherboard.)

> 
> Best, :-)
> Marko
> 
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
> 
>   
>

-- 
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software-- http://www.deepsoft.com/
()  ascii ribbon campaign -- against html e-mail
/\  www.asciiribbon.org   -- against proprietary attachments


 
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Devin Reade]

Ljubomir Ljubojevic  wrote:

> First is to have LAN power controller/switch, can't remember how you 
> call it. It can monitor several inputs like voltage, on/off, etc, and it 
> can be used to cut and restore power, as well as reboot. They have web 
> interface and are accessible via IP. Wireless network guys use them.

I do in fact use these (they're called managed power distribution units,
such as the APC AP7900), not only for such manual operations but also
because they're good for doing fencing in HA clusters.

However, that does not alter the fact that this solution requires
human intervention (albiet in this case you can do it remotely).
It doesn't fix the flaw, it just works around it.

It's also an additional expense that I don't think would be in the
OP's scope.

Devin

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Ljubomir Ljubojevic]

Devin Reade wrote:
> There is one flaw that I know of with APC brand UPSes, although I wouldn't
> be surprised if other UPSes are similar (since APC has traditionally
> set the standard in the market):  There is a small window between
> the time that the UPS initiates a shutdown and the control software
> (such as apcupsd) tells the UPS to kill power in (some number of) seconds.
> If your mains power returns and stays on during that window, your
> machine may not restart by itself:  It may be too late to cancel the
> OS shutdown and subsequent power-off, but because the UPS still has
> mains power it doesn't trigger the power cycle that allows the computer
> to reboot (assuming you've configured your BIOS to boot at power-on).
> In my experience this doesn't happen often (I've seen it probably
> twice in 15 years), but it does happen and can be a real PITA if 
> you don't have anyone on site that can deal with it.

This can be solved with several approaches.

First is to have LAN power controller/switch, can't remember how you 
call it. It can monitor several inputs like voltage, on/off, etc, and it 
can be used to cut and restore power, as well as reboot. They have web 
interface and are accessible via IP. Wireless network guys use them.

Another approach is to have power switch power by mobile/cell phone. You 
call the number and it effectively cuts power for a desired period of time.

Ljubomir
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Nichols]

On 07/02/2011 12:07 PM, Devin Reade wrote:
> There is one flaw that I know of with APC brand UPSes, although I wouldn't
> be surprised if other UPSes are similar (since APC has traditionally
> set the standard in the market):  There is a small window between
> the time that the UPS initiates a shutdown and the control software
> (such as apcupsd) tells the UPS to kill power in (some number of) seconds.
> If your mains power returns and stays on during that window, your
> machine may not restart by itself:  It may be too late to cancel the
> OS shutdown and subsequent power-off, but because the UPS still has
> mains power it doesn't trigger the power cycle that allows the computer
> to reboot (assuming you've configured your BIOS to boot at power-on).
> In my experience this doesn't happen often (I've seen it probably
> twice in 15 years), but it does happen and can be a real PITA if
> you don't have anyone on site that can deal with it.

Fix the shutdown sequence so that after killing the UPS, and right at the
point where you would tell the BIOS to turn off the ATX power supply, the
machine sleeps for a few seconds (longer than it should take for power to
drop) and then reboots instead of shutting down.  If commercial power has
returned, you just reboot.  If not, power is removed at a safe point.

-- 
Bob Nichols "NOSPAM" is really part of my email address.
 Do NOT delete it.

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Les Mikesell]

On 7/2/11 12:58 PM, Marko Vojinovic wrote:
>
> If a laptop can have several *different* and *precise* voltages from a single
> DC battery, why the desktop cannot?

If you are facebook, you can design/demand whatever you want, including 
single-voltage motherboards.  Not sure why everyone else put up with the 
problem 
for so long.

http://perspectives.mvdirona.com/2011/04/21/OpenComputeServerDesign.aspx

-- 
   Les Mikesell
lesmikes...@gmail.com

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jason Pyeron]

> -Original Message-
> From: centos-boun...@centos.org 
> [mailto:centos-boun...@centos.org] On Behalf Of Marko Vojinovic
> Sent: Saturday, July 02, 2011 13:58
> To: CentOS mailing list
> Subject: Re: [CentOS] Power-outage
> 
> On Saturday 02 July 2011 18:21:27 Jason Pyeron wrote:
> > > > > But surely computers actually use DC, so couldn't my 
> > > > > torch-battery device just supply the PC components directly?
> > > > 
> > > > A PC uses several *different* DC voltages: +12, +5, +3.3, and 
> > > > several others and they need to be *precise*.  Some of 
> these are 
> > > > not an exact multiples of the standard 1.5V Carbon-Zinc cells 
> > > > typicaly used in torch batteries.
> > > 
> > > I wonder, how is this issue solved in laptops? They use 
> only one DC 
> > > battery, typically with a single voltage output, AFAIK.
> > 
> > (sorry ctrl-enter sends...)
> > 
> > Laptops, google mother boards, etc have power supply 
> circuits on board.
> > Remember that a switching powersupply taking AC still has dc to dc 
> > converters in it after the conditioning stage.
> 
> So couldn't the OP then plug a battery "in between" (I'm 
> talking in principle here, not realistically) --- after the 
> AC-to-DC stage but before the "conditioning" stage?
> 
> If a laptop can have several *different* and *precise* 
> voltages from a single DC battery, why the desktop cannot?
> 
> I am not saying that it would be easy or cheap, just that the 

But the OP wanted cheap. Nor would it be easy.

> above "different voltages" argument seems false from my POV. 
> If a laptop can be battery- powered, so can a desktop (given 
> that you have all the hardware to implement it). You don't 

There is lies the rub, it is easier and cheaper to buy one, but it is even
cheaper and easier to buy an UPS. The UPS comes with insurance too.

> need to tweak the motherboard, just the PSU. It's routinely 
> done in laptops, so it doesn't seem to be rocket-science or 
> something too expensive. I wonder why aren't there any 
> desktops on the market with same technology?

Because, it is more expensive in a world where 110 or 220 AC is standard. Our
server room has DC supply for critical infrastructure, but that costs more to
maintain and install. The battery room requires fire and enviromental equipment
and configuration, the personnel who enter the room require certification and
training on how to handle acid, hydrogen, fires, spills, etc. The electrical
infrastructure required extra time and money to install because the local code
did not have rules for high amprage extra low voltace (50V 
> I'm using an UPS for my desktop system, but I don't need it 
> for the laptop. If the AC power drops, even for a moment, the 

They are also low wattage, http://www.indocomp.com/ind-ups200-atx-spec.html,
http://www.eurasiapower.com/power_supply_eu_eUPS-350.asp,
http://www.apollo.com.tw/products_data.html

> laptop battery will kick in and sustain the machine. I just 
> think that the same thing can be implemented for the desktop 
> too. If I understood the OP correctly... ;-)
> 

--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-   -
- Jason Pyeron  PD Inc. http://www.pdinc.us -
- Principal Consultant  10 West 24th Street #100-
- +1 (443) 269-1555 x333Baltimore, Maryland 21218   -
-   -
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
This message is copyright PD Inc, subject to license 20080407P00.

 

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Saturday 02 July 2011 18:21:27 Jason Pyeron wrote:
> > > > But surely computers actually use DC, so couldn't my
> > > > torch-battery
> > > > device just supply the PC components directly?
> > > 
> > > A PC uses several *different* DC voltages: +12, +5, +3.3,
> > > and several
> > > others and they need to be *precise*.  Some of these are
> > > not an exact
> > > multiples of the standard 1.5V Carbon-Zinc cells typicaly used in
> > > torch batteries.
> > 
> > I wonder, how is this issue solved in laptops? They use only
> > one DC battery, typically with a single voltage output, AFAIK.
> 
> (sorry ctrl-enter sends...)
> 
> Laptops, google mother boards, etc have power supply circuits on board.
> Remember that a switching powersupply taking AC still has dc to dc
> converters in it after the conditioning stage.

So couldn't the OP then plug a battery "in between" (I'm talking in principle 
here, not realistically) --- after the AC-to-DC stage but before the 
"conditioning" stage?

If a laptop can have several *different* and *precise* voltages from a single 
DC battery, why the desktop cannot?

I am not saying that it would be easy or cheap, just that the above "different 
voltages" argument seems false from my POV. If a laptop can be battery-
powered, so can a desktop (given that you have all the hardware to implement 
it). You don't need to tweak the motherboard, just the PSU. It's routinely 
done in laptops, so it doesn't seem to be rocket-science or something too 
expensive. I wonder why aren't there any desktops on the market with same 
technology?

I'm using an UPS for my desktop system, but I don't need it for the laptop. If 
the AC power drops, even for a moment, the laptop battery will kick in and 
sustain the machine. I just think that the same thing can be implemented for 
the desktop too. If I understood the OP correctly... ;-)

Best, :-)
Marko


___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jason Pyeron]

> -Original Message-
> From: centos-boun...@centos.org 
> [mailto:centos-boun...@centos.org] On Behalf Of Marko Vojinovic
> Sent: Saturday, July 02, 2011 13:10
> To: CentOS mailing list
> Subject: Re: [CentOS] Power-outage
> 
> On Saturday 02 July 2011 15:45:11 Robert Heller wrote:
> > At Sat, 02 Jul 2011 14:52:27 +0200 CentOS mailing list 
> > 
> wrote:
> > > Emmanuel Noobadmin wrote:
> > > >> It seems to me that it should be possible to have a simple, 
> > > >> torch-battery operated, system which will keep the 
> machine alive 
> > > >> long enough to make a graceful exit.
> > > > 
> > > > The problem
> > > > with your idea is that you'll need a DC to AC inverter that can 
> > > > handle the output current required by your server and 
> something to 
> > > > hold the batteries (you'll need more than one because 
> attempting 
> > > > to draw a huge current from a normal battery will 
> either kill it 
> > > > or at the very least cause it to have a shorter than expected 
> > > > capacity) and everything together, it's probably going to cost 
> > > > more in both money and time to have this thing.
> > > 
> > > I'm sure you are right, as I know nothing at all about 
> power supplies.
> > > But surely computers actually use DC, so couldn't my 
> torch-battery 
> > > device just supply the PC components directly?
> > 
> > A PC uses several *different* DC voltages: +12, +5, +3.3, 
> and several 
> > others and they need to be *precise*.  Some of these are 
> not an exact 
> > multiples of the standard 1.5V Carbon-Zinc cells typicaly used in 
> > torch batteries.
> 
> I wonder, how is this issue solved in laptops? They use only 
> one DC battery, typically with a single voltage output, AFAIK.
> 

(sorry ctrl-enter sends...)

Laptops, google mother boards, etc have power supply circuits on board. Remember
that a switching powersupply taking AC still has dc to dc converters in it after
the conditioning stage.


--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-   -
- Jason Pyeron  PD Inc. http://www.pdinc.us -
- Principal Consultant  10 West 24th Street #100-
- +1 (443) 269-1555 x333Baltimore, Maryland 21218   -
-   -
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
This message is copyright PD Inc, subject to license 20080407P00.

 

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jason Pyeron]

> -Original Message-
> From: centos-boun...@centos.org 
> [mailto:centos-boun...@centos.org] On Behalf Of Marko Vojinovic
> Sent: Saturday, July 02, 2011 13:10
> To: CentOS mailing list
> Subject: Re: [CentOS] Power-outage
> 
> On Saturday 02 July 2011 15:45:11 Robert Heller wrote:
> > At Sat, 02 Jul 2011 14:52:27 +0200 CentOS mailing list 
> > 
> wrote:
> > > Emmanuel Noobadmin wrote:
> > > >> It seems to me that it should be possible to have a simple, 
> > > >> torch-battery operated, system which will keep the 
> machine alive 
> > > >> long enough to make a graceful exit.
> > > > 
> > > > The problem
> > > > with your idea is that you'll need a DC to AC inverter that can 
> > > > handle the output current required by your server and 
> something to 
> > > > hold the batteries (you'll need more than one because 
> attempting 
> > > > to draw a huge current from a normal battery will 
> either kill it 
> > > > or at the very least cause it to have a shorter than expected 
> > > > capacity) and everything together, it's probably going to cost 
> > > > more in both money and time to have this thing.
> > > 
> > > I'm sure you are right, as I know nothing at all about 
> power supplies.
> > > But surely computers actually use DC, so couldn't my 
> torch-battery 
> > > device just supply the PC components directly?
> > 
> > A PC uses several *different* DC voltages: +12, +5, +3.3, 
> and several 
> > others and they need to be *precise*.  Some of these are 
> not an exact 
> > multiples of the standard 1.5V Carbon-Zinc cells typicaly used in 
> > torch batteries.
> 
> I wonder, how is this issue solved in laptops? They use only 
> one DC battery, typically with a single voltage output, AFAIK.
> 
> Best, :-)
> Marko
> 
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
> 

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Marko Vojinovic]

On Saturday 02 July 2011 15:45:11 Robert Heller wrote:
> At Sat, 02 Jul 2011 14:52:27 +0200 CentOS mailing list  
wrote:
> > Emmanuel Noobadmin wrote:
> > >> It seems to me that it should be possible
> > >> to have a simple, torch-battery operated, system
> > >> which will keep the machine alive long enough
> > >> to make a graceful exit.
> > > 
> > > The problem
> > > with your idea is that you'll need a DC to AC inverter that can handle
> > > the output current required by your server and something to hold the
> > > batteries (you'll need more than one because attempting to draw a huge
> > > current from a normal battery will either kill it or at the very least
> > > cause it to have a shorter than expected capacity) and everything
> > > together, it's probably going to cost more in both money and time to
> > > have this thing.
> > 
> > I'm sure you are right, as I know nothing at all about power supplies.
> > But surely computers actually use DC,
> > so couldn't my torch-battery device just supply the PC components
> > directly?
> 
> A PC uses several *different* DC voltages: +12, +5, +3.3, and several
> others and they need to be *precise*.  Some of these are not an exact
> multiples of the standard 1.5V Carbon-Zinc cells typicaly used in torch
> batteries.

I wonder, how is this issue solved in laptops? They use only one DC battery, 
typically with a single voltage output, AFAIK.

Best, :-)
Marko

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Devin Reade]

Bowie Bailey  wrote:

> If you don't require a long runtime, then you don't need
> to get a huge UPS.  APC's website has a calculator that can help you
> determine which UPS will work best based on your equipment and desired
> runtime.

However, give yourself some leeway to allow not only for changes in your
usage pattern (addition of hardware or changing hardware) but also 
degradation of the battery over time.

I've generally found that if you're pushing a UPS past 70-85% capacity,
you may not (depending on the system) have sufficient runtime to shut
down completely before exhausting the battery.  Other things to take 
into account is if you have programs that take a while to shut down
(some databases can take a *very* long time) and whether or not you
have to power auxilliary equipment such as monitor during an outage.

I usually like to have a UPS loaded to only 50%.  That gives a decent
enough battery time for either allowing an extended shutdown time or
for carrying the system through multiple short failures without 
bringing the system down at all.

There is one flaw that I know of with APC brand UPSes, although I wouldn't
be surprised if other UPSes are similar (since APC has traditionally
set the standard in the market):  There is a small window between
the time that the UPS initiates a shutdown and the control software
(such as apcupsd) tells the UPS to kill power in (some number of) seconds.
If your mains power returns and stays on during that window, your
machine may not restart by itself:  It may be too late to cancel the
OS shutdown and subsequent power-off, but because the UPS still has
mains power it doesn't trigger the power cycle that allows the computer
to reboot (assuming you've configured your BIOS to boot at power-on).
In my experience this doesn't happen often (I've seen it probably
twice in 15 years), but it does happen and can be a real PITA if 
you don't have anyone on site that can deal with it.

Devin

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[fred smith]

On Sat, Jul 02, 2011 at 10:45:13AM -0400, Robert Heller wrote:
> At Sat, 02 Jul 2011 15:42:38 +0200 CentOS mailing list  
> wrote:
> 
> > 
> > Jason Pyeron wrote:
> > 
> > >> Could you (or anyone) suggest a cheap UPS?
> > >> This is only a tiny server (HP MicroServer) on a home LAN.
> > > 
> > > http://www.amazon.com/APC-Back-UPS-shutdown-software-UPS-
> > BE350G/dp/B001985SWW/
> > 
> > Thanks, I'll look into that.
> > 
> > >> I'm sure you are right, as I know nothing at all about power supplies.
> > >> But surely computers actually use DC,
> > >> so couldn't my torch-battery device just supply the PC
> > >> components directly?
> > 
> > > You will either need many different batteries for the different voltages
> > > (1.2, 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not
> > > very powerful until the 48V input variety)
> > 
> > Surely one 12v battery would do?
> 
> Actually not. You need both positive and negative voltages.  You cannot
> just use a 12v battery with a voltage divider resistor network.  And
> because the voltages needed have to be precise, you really need a
> properly regulated power supply.  Like Jason said, it would be a 48VDC
> input unit and will cost you many times what a cheap UPS would cost.
> 
> > It is only meant to last for 30 seconds or so,
> > so wouldn't reducing the voltage be easy enough?
> > I repeat that I don't know what I'm talking about ...
> > 
> 
I believe Google runs bazillions of servers with a PS that emits 12 v,
a 12v battery on the downstream side of the PS, and a custom motherboard
that requires only 12V input. If not exactly those specs, at least that
sort of thing. But Google uses so many tens of thousands of 'em that it
is economical for them to have them custom-made, whereas you want one,
so it'd cost you a fortune. (there have been a few articles on various
web sites over the last year or two showing Google's server internals.)

So, in theory you could do something akin to what you ask, but in
practice it would be much cheaper for you to spend a few bucks for a
low-spec UPS unit. assuming the server has no peripherals that require
power (such as a monitor) and it is a low-power device like a micro-ATX
board with an Atom processor, or someting of that ilk, a small-ish UPS
would work fine. Such low-spec UPS units are inexpensive.

-- 
 Fred Smith -- fre...@fcshome.stoneham.ma.us -
  "For him who is able to keep you from falling and to present you before his 
 glorious presence without fault and with great joy--to the only God our Savior
 be glory, majesty, power and authority, through Jesus Christ our Lord, before
 all ages, now and forevermore! Amen."
- Jude 1:24,25 (niv) -
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Sat, 02 Jul 2011 15:42:38 +0200 CentOS mailing list  
wrote:

> 
> Jason Pyeron wrote:
> 
> >> Could you (or anyone) suggest a cheap UPS?
> >> This is only a tiny server (HP MicroServer) on a home LAN.
> > 
> > http://www.amazon.com/APC-Back-UPS-shutdown-software-UPS-
> BE350G/dp/B001985SWW/
> 
> Thanks, I'll look into that.
> 
> >> I'm sure you are right, as I know nothing at all about power supplies.
> >> But surely computers actually use DC,
> >> so couldn't my torch-battery device just supply the PC
> >> components directly?
> 
> > You will either need many different batteries for the different voltages
> > (1.2, 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not
> > very powerful until the 48V input variety)
> 
> Surely one 12v battery would do?

Actually not. You need both positive and negative voltages.  You cannot
just use a 12v battery with a voltage divider resistor network.  And
because the voltages needed have to be precise, you really need a
properly regulated power supply.  Like Jason said, it would be a 48VDC
input unit and will cost you many times what a cheap UPS would cost.

> It is only meant to last for 30 seconds or so,
> so wouldn't reducing the voltage be easy enough?
> I repeat that I don't know what I'm talking about ...
> 

-- 
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software-- http://www.deepsoft.com/
()  ascii ribbon campaign -- against html e-mail
/\  www.asciiribbon.org   -- against proprietary attachments


 
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Sat, 02 Jul 2011 14:52:27 +0200 CentOS mailing list  
wrote:

> 
> Emmanuel Noobadmin wrote:
> 
> >> It seems to me that it should be possible
> >> to have a simple, torch-battery operated, system
> >> which will keep the machine alive long enough
> >> to make a graceful exit.
> 
> > Like others have suggested, a cheap UPS is the way to go.
> 
> I'm convinced.
> Could you (or anyone) suggest a cheap UPS?
> This is only a tiny server (HP MicroServer) on a home LAN.
> 
> > The problem
> > with your idea is that you'll need a DC to AC inverter that can handle
> > the output current required by your server and something to hold the
> > batteries (you'll need more than one because attempting to draw a huge
> > current from a normal battery will either kill it or at the very least
> > cause it to have a shorter than expected capacity) and everything
> > together, it's probably going to cost more in both money and time to
> > have this thing.
> 
> I'm sure you are right, as I know nothing at all about power supplies.
> But surely computers actually use DC,
> so couldn't my torch-battery device just supply the PC components directly?

A PC uses several *different* DC voltages: +12, +5, +3.3, and several
others and they need to be *precise*.  Some of these are not an exact
multiples of the standard 1.5V Carbon-Zinc cells typicaly used in torch
batteries.

> 
> Many decades ago I went to lectures at university given by Fred Hoyle
> (famous at the time for a TV series where he said God was unnecessary).
> The lectures (on thermodynamics) were not really very good,
> but they were interesting because Fred Hoyle was slighly paranoid,
> and believed evil capitalists were foisting unnecessary devices on us.
> 
> One of his pet theories was that cars did not need huge accumulators,
> but could be started with a torch-battery.
> 
> Another was that incandescent bulbs were deliberately made to fail
> after a certain time.
> 
> Another was razor blades, which according to him could easily last for ever.
> 
> One interesting idea was that instead of nuclear power stations
> it would be cheaper, and give the same energy, to plant trees
> in a strip around the equator (I forget how wide).
> 
> 
> 
> 
> 
> 

-- 
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software-- http://www.deepsoft.com/
()  ascii ribbon campaign -- against html e-mail
/\  www.asciiribbon.org   -- against proprietary attachments


 
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jussi Hirvi]

On 1.7.2011 18.49, m.r...@5-cent.us wrote:
> ah, the smell of fresh plastic outgassing, factory
> air from China :(((

Probably more the smell of fire prevention chemicals outgassing. Be 
careful! As for me, I am sensitized to that smell.

- Jussi
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jussi Hirvi]

On 1.7.2011 18.49, m.r...@5-cent.us wrote:
> ah, the smell of fresh plastic outgassing, factory
> air from China :(((

Probably more the smell of fire prevention chemicals outgassing. Be 
careful! I am sensitized to that smell.

- Jussi
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Christopher Chan]

On Saturday, July 02, 2011 09:42 PM, Timothy Murphy wrote:
> Jason Pyeron wrote:
>
>>> Could you (or anyone) suggest a cheap UPS?
>>> This is only a tiny server (HP MicroServer) on a home LAN.
>>
>> http://www.amazon.com/APC-Back-UPS-shutdown-software-UPS-
> BE350G/dp/B001985SWW/
>
> Thanks, I'll look into that.
>
>>> I'm sure you are right, as I know nothing at all about power supplies.
>>> But surely computers actually use DC,
>>> so couldn't my torch-battery device just supply the PC
>>> components directly?
>
>> You will either need many different batteries for the different voltages
>> (1.2, 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not
>> very powerful until the 48V input variety)
>
> Surely one 12v battery would do?
> It is only meant to last for 30 seconds or so,
> so wouldn't reducing the voltage be easy enough?
> I repeat that I don't know what I'm talking about ...
>

The PSU transforms incoming electricity to various voltages on multiple 
rails. You need more than just a 12V lead acid battery.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Jason Pyeron wrote:

>> Could you (or anyone) suggest a cheap UPS?
>> This is only a tiny server (HP MicroServer) on a home LAN.
> 
> http://www.amazon.com/APC-Back-UPS-shutdown-software-UPS-
BE350G/dp/B001985SWW/

Thanks, I'll look into that.

>> I'm sure you are right, as I know nothing at all about power supplies.
>> But surely computers actually use DC,
>> so couldn't my torch-battery device just supply the PC
>> components directly?

> You will either need many different batteries for the different voltages
> (1.2, 3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not
> very powerful until the 48V input variety)

Surely one 12v battery would do?
It is only meant to last for 30 seconds or so,
so wouldn't reducing the voltage be easy enough?
I repeat that I don't know what I'm talking about ...

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jason Pyeron]

> -Original Message-
> From: centos-boun...@centos.org 
> [mailto:centos-boun...@centos.org] On Behalf Of Timothy Murphy
> Sent: Saturday, July 02, 2011 8:52
> To: centos@centos.org
> Subject: Re: [CentOS] Power-outage
> 
> Emmanuel Noobadmin wrote:
> 
> >> It seems to me that it should be possible to have a simple, 
> >> torch-battery operated, system which will keep the machine 
> alive long 
> >> enough to make a graceful exit.
> 
> > Like others have suggested, a cheap UPS is the way to go.
> 
> I'm convinced.
> Could you (or anyone) suggest a cheap UPS?
> This is only a tiny server (HP MicroServer) on a home LAN.

http://www.amazon.com/APC-Back-UPS-shutdown-software-UPS-BE350G/dp/B001985SWW/

> 
> > The problem
> > with your idea is that you'll need a DC to AC inverter that 
> can handle 
> > the output current required by your server and something to 
> hold the 
> > batteries (you'll need more than one because attempting to 
> draw a huge 
> > current from a normal battery will either kill it or at the 
> very least 
> > cause it to have a shorter than expected capacity) and everything 
> > together, it's probably going to cost more in both money 
> and time to 
> > have this thing.
> 
> I'm sure you are right, as I know nothing at all about power supplies.
> But surely computers actually use DC,
> so couldn't my torch-battery device just supply the PC 
> components directly?
> 

You will either need many different batteries for the different voltages (1.2,
3.3, 5, 12, -12, -5) or a DC ATX power supply (not cheap and not very powerful
until the 48V input variety)


> Many decades ago I went to lectures at university given by 
> Fred Hoyle (famous at the time for a TV series where he said 
> God was unnecessary).
> The lectures (on thermodynamics) were not really very good, 
> but they were interesting because Fred Hoyle was slighly 
> paranoid, and believed evil capitalists were foisting 
> unnecessary devices on us.
> 
> One of his pet theories was that cars did not need huge 
> accumulators, but could be started with a torch-battery.
> 
> Another was that incandescent bulbs were deliberately made to 
> fail after a certain time.
> 
> Another was razor blades, which according to him could easily 
> last for ever.
> 
> One interesting idea was that instead of nuclear power 
> stations it would be cheaper, and give the same energy, to 
> plant trees in a strip around the equator (I forget how wide).
> 
> 
> 
> 
> 
> 
> --
> Timothy Murphy
> e-mail: gayleard /at/ eircom.net
> tel: +353-86-2336090, +353-1-2842366
> s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland
> 
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
> 

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Emmanuel Noobadmin wrote:

>> It seems to me that it should be possible
>> to have a simple, torch-battery operated, system
>> which will keep the machine alive long enough
>> to make a graceful exit.

> Like others have suggested, a cheap UPS is the way to go.

I'm convinced.
Could you (or anyone) suggest a cheap UPS?
This is only a tiny server (HP MicroServer) on a home LAN.

> The problem
> with your idea is that you'll need a DC to AC inverter that can handle
> the output current required by your server and something to hold the
> batteries (you'll need more than one because attempting to draw a huge
> current from a normal battery will either kill it or at the very least
> cause it to have a shorter than expected capacity) and everything
> together, it's probably going to cost more in both money and time to
> have this thing.

I'm sure you are right, as I know nothing at all about power supplies.
But surely computers actually use DC,
so couldn't my torch-battery device just supply the PC components directly?

Many decades ago I went to lectures at university given by Fred Hoyle
(famous at the time for a TV series where he said God was unnecessary).
The lectures (on thermodynamics) were not really very good,
but they were interesting because Fred Hoyle was slighly paranoid,
and believed evil capitalists were foisting unnecessary devices on us.

One of his pet theories was that cars did not need huge accumulators,
but could be started with a torch-battery.

Another was that incandescent bulbs were deliberately made to fail
after a certain time.

Another was razor blades, which according to him could easily last for ever.

One interesting idea was that instead of nuclear power stations
it would be cheaper, and give the same energy, to plant trees
in a strip around the equator (I forget how wide).






-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Christopher Chan]

On Friday, July 01, 2011 11:46 PM, Brunner, Brian T. wrote:
> centos-boun...@centos.org wrote:
>> On 7/1/2011 10:59 AM, Robert Heller wrote:
>>>
>>> APC UPSes are supported by apcupsd.  Other brands, not so much.  Some
>>> (read: cheaper models) have their own special protocol and don't
>>> include Linux support.  These solutions are intended for the cheaper
>>> or otherwise 'unsupported' UPSes.  It *sounds* like the OP does not
>>> need something smart and is probably looking for something cheap.
>>>
>>
>> And the APC Smart-UPS 750 units are not all that expensive
>> either.  Even the 1500VA units are a lot less expensive then they were
> 5-10
>> years ago.   $250-$300 to protect $2000-$6000 worth of hardware is
> worth
>> it in my book.
>
> To what extent does a UPS *protect* the hardware?
> Maintaining up-time during brief brown-outs is one thing I expect of a
> UPS,
> Orderly shutdown is another thing I expect of a UPS.
>
> *protection* of the PC from irregularity in the AC Mains by a UPS,
> however, I question.
> Rather, it seems, any power irregularity that would kill a PC by
> propagating through the PSU will also propagate through the UPS.
>

PSUs must love Regular under voltage electricity and so too your data if 
the batteries of the UPS are anything to go by. Batteries died within 
two years on one particular circuit and the connected servers suffered 
while I was getting replacement batteries. Apparently one motherboard 
loved it so much that the thing would not POST anymore.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/1/11, Robert Heller  wrote:
> At Fri, 01 Jul 2011 16:25:33 +0200 CentOS mailing list 
> wrote:
>
>>
>> Colin Coles wrote:

>> perhaps naively, I'm surprised: doesn't this mean they put crappy PSUs
>> in those servers?
>> I thought decent PSUs were expected to deal with dirty input AC?
>
> AND *I* thought *switching power supplies* (effectively) rectified the
> AC input and then used the DC to drive a higher frequency system to get
> the desired output voltages.  (The higher frequency means smaller, more
> efficient transformers and need smaller filter caps -- all of which
> means a lower cost, more reliable, more efficient power supply.)  Which
> suggests that both the input voltage and frequency are not particularly
> critical, so long as it does not have massive spikes/surges or
> consistently low voltage.

In a normal SMPS that would be true, because the typical ATX PSU
normally has two bulk input capacitors. However the better PSUs
nowadays and those in servers are usually active PFC units which only
has one.

Now the problem occurs because non-true sinewave UPS usually use PWM
to achieve the output. This means the UPS outputs a consistent high
voltage but switches it on/off to achieve the same average power, i.e.
400V for x msec, then 0V for x msec = 200V average, where x should be
much smaller than 16 msec IIRC, which is the required hold up time for
ATX specifications.


In a cheap and arguably badly designed UPS, the selected voltage is
much higher than the PSU is expected to ever handle from a true
sine-wave source (which is nominally 320V peak for a 230V RMS source).
So it either blows the input capacitors (typically 400V values), or
protective circuitry shuts it down first. On the non-PFC PSU, the
voltage is divided across the two main caps so this isn't a problem.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Emmanuel Noobadmin]

On 7/1/11, Timothy Murphy  wrote:
> It seems to me that it should be possible
> to have a simple, torch-battery operated, system
> which will keep the machine alive long enough
> to make a graceful exit.
> A full-blown UPS would be excessive, I think,
> as I only want the machine to re-boot
> when the current comes back on.

Like others have suggested, a cheap UPS is the way to go. The problem
with your idea is that you'll need a DC to AC inverter that can handle
the output current required by your server and something to hold the
batteries (you'll need more than one because attempting to draw a huge
current from a normal battery will either kill it or at the very least
cause it to have a shorter than expected capacity) and everything
together, it's probably going to cost more in both money and time to
have this thing.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Jim Nelson]

On 7/1/2011 1:02 PM, Brunner, Brian T. wrote:
> centos-boun...@centos.org wrote:
>> Brunner, Brian T. wrote:
>>> centos-boun...@centos.org wrote:
>>>
 And the APC Smart-UPS 750 units are not all that expensive
 either.  Even the 1500VA units are a lot less expensive then they
 were 5-10 years ago.   $250-$300 to protect $2000-$6000 worth
>> of hardware is worth it in my book.
>>>
>>> To what extent does a UPS *protect* the hardware?
>>> Maintaining up-time during brief brown-outs is one thing I expect of
>>> a UPS,Orderly shutdown is another thing I expect of a UPS.
>>>
>>> *protection* of the PC from irregularity in the AC Mains by a UPS,
>>> however, I question. Rather, it seems, any power irregularity that
>>> would kill a PC by propagating through the PSU will also propagate
>>> through the UPS.
>>>
>>> NO UPS MADE TODAY (according to my reading of the stats on
>>> advertisements) eats lightning strikes and asks for more.
>>>
>>> So per your experiences and greater technical savvy: What PSU/PC kill
>>> power irregularities will be stopped by which UPS?
>>
>> Really? That's what you read in the specs?
>
> Yes.  Compare the joules rating (as being stopped by a UPS with surge
> suppression)
> to the joules required to damage the computer on the other side of a
> PSU.
> So per your experiences and greater technical savvy: What PSU/PC kill
> power irregularities will be stopped by which UPS?
>
> Robert Heller suggested that UPS architecture matters:
> AC->DC::DC Batteries::DC->AC
> Where input AC is electrically decoupled from output AC.
> Not many adverts for UPS's explain whether this is the case with their
> UPS.
>

APC's SmartUPS line, Liebert, and Eaton Powerware are all true-sine wave UPS's, 
and do proper decoupling. Unfortunately, this kind 
of data doesn't make for great ad copy, so it's left out, and you have to dig 
deep into datasheets to get that information. I pretty 
much only use APC, and we have truly crap power here. Because of some heavy 
industry in the area, brownouts are common, and that'll 
kill a PC power supply better than anything. I've pulled one 7 year old APC 
from a server closet where the lightning took the top of 
the telephone pole OFF. THE UPS was fried, some of the breakers in the building 
were fused (!), but the servers were fine, outside 
of the router that got zapped from the DSL modem.

The advantage to better UPS systems is they dump the input power through a big, 
beefy transformer. That provides enough of an 
inductor that it can eat a HUGE surge before the insulation in the transformer 
breaks down and it arcs across to the output. Even 
then, it has a long way to go before it can hit the output circuits.

So, your cheap $100 UPS won't provide as much protection from a nasty spike, 
but it would be VERY rare to see a spike that big.

>> Here, I thought that good quality surge protectors would do that,
>> and my UPS does says surge protection as well as UPS. IIRC, UPSs, and
> better surge
>> protectors, offer a multi-thousand dollar warranty if it doesn't stop
> a large
>> surge and your system's fried.
>
> Have you tried collecting on said warranties?
> Be prepared to prove that the surge that fried your hardware did not
> exceed the joules rating on the surge suppressor.
>

And that's why you don't go cheap on your UPSs. Overbuilding capacity means you 
get a longer run time - and you also have room for 
expansion. Cheaper to go big early.

>
> Insert spiffy .sig here:
> Life is complex: it has both real and imaginary parts.
> Life is not measured by the number of breaths we take, but by the
> moments that take our breath away.
>
>
> //me
> ***
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom
> they are addressed. If you have received this email in error please
> notify the system manager. This footnote also confirms that this
> email message has been swept for the presence of computer viruses.
> www.Hubbell.com - Hubbell Incorporated**
>
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
>


-- 
Jim Nelson
Systems Administrator, Broadtime
(888) 582-3229
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Brunner, Brian T.]

centos-boun...@centos.org wrote:
> Brunner, Brian T. wrote:
>> centos-boun...@centos.org wrote:
>> 
>>> And the APC Smart-UPS 750 units are not all that expensive
>>> either.  Even the 1500VA units are a lot less expensive then they
>>> were 5-10 years ago.   $250-$300 to protect $2000-$6000 worth
> of hardware is worth it in my book.
>> 
>> To what extent does a UPS *protect* the hardware?
>> Maintaining up-time during brief brown-outs is one thing I expect of
>> a UPS,Orderly shutdown is another thing I expect of a UPS.
>> 
>> *protection* of the PC from irregularity in the AC Mains by a UPS,
>> however, I question. Rather, it seems, any power irregularity that
>> would kill a PC by propagating through the PSU will also propagate
>> through the UPS. 
>> 
>> NO UPS MADE TODAY (according to my reading of the stats on
>> advertisements) eats lightning strikes and asks for more.
>> 
>> So per your experiences and greater technical savvy: What PSU/PC kill
>> power irregularities will be stopped by which UPS?
> 
> Really? That's what you read in the specs? 

Yes.  Compare the joules rating (as being stopped by a UPS with surge
suppression) 
to the joules required to damage the computer on the other side of a
PSU.
So per your experiences and greater technical savvy: What PSU/PC kill
power irregularities will be stopped by which UPS?

Robert Heller suggested that UPS architecture matters:
AC->DC::DC Batteries::DC->AC
Where input AC is electrically decoupled from output AC.
Not many adverts for UPS's explain whether this is the case with their
UPS.

> Here, I thought that good quality surge protectors would do that, 
> and my UPS does says surge protection as well as UPS. IIRC, UPSs, and
better surge
> protectors, offer a multi-thousand dollar warranty if it doesn't stop
a large
> surge and your system's fried.

Have you tried collecting on said warranties?
Be prepared to prove that the surge that fried your hardware did not
exceed the joules rating on the surge suppressor.


Insert spiffy .sig here:
Life is complex: it has both real and imaginary parts.
Life is not measured by the number of breaths we take, but by the
moments that take our breath away. 


//me
***
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom
they are addressed. If you have received this email in error please
notify the system manager. This footnote also confirms that this
email message has been swept for the presence of computer viruses.
www.Hubbell.com - Hubbell Incorporated**

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Fri, 01 Jul 2011 17:36:56 +0100 CentOS mailing list  
wrote:

> 
> Rudi Ahlers wrote:
> 
> >> It seems to me that it should be possible
> >> to have a simple, torch-battery operated, system
> >> which will keep the machine alive long enough
> >> to make a graceful exit.
> 
> > A UPS would be your simplest option here since the UPS can send a
> > signal to the OS to shutdown properly.
> > 
> > Using a "torch battery" (I presume this is a large torch?) you'll
> > still have the same issue as you have now - when the battery runs flat
> > (i.e. power outage is longer than 10 minutes or so) Linux will still
> > crash uncleanly.
> 
> As will be obvious, I know nothing in this area.
> My thought was just that the machine only requires say 30 seconds of life
> to shutdown properly, and I would have thought
> there was enough capacity in a large torch battery to supply this?

What do you mean by 'torch battery'? If you mean the D cells typical of
a flashlight (flashlight is 'American' English for [electric] torch),
no this is not going to power a computer for more than fraction of a
second.  If you mean a 'lattern battery' (a larger 6V battery, used in
typical upright camping latterns), maybe, but you are going to need an
inverter, etc. to feed AC to your computer's power supply.

> 
> But there seems to be a 100% backing for UPS,
> so I'll look into that.

Yes. They are not terribly expensive, partitularly if you are not
looking for a large one or a 'fancy' (excessive 'bells and whistles')
one. For a small server, a typical consumer-grade UPS costing like
US$100 will do everything you need.

These little consumer-grade UPSes, basically consist of a rechargable
'lattern battery' sized rechargable battery (commonly a gel-cell
lead-acid type battery), a charger for the battery, and an inverter to
re-create the AC power for your equipment (computer).  All in one box. 
Most now have some simple 'smart' electronics with a simple
micro-processor element with a USB connection that will talk to your
computer telling it how things are going (on Mains, on battery, battery
charging, battery charged, battery discharged, current load levels,
Mains voltage, etc.).

> 

-- 
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software-- http://www.deepsoft.com/
()  ascii ribbon campaign -- against html e-mail
/\  www.asciiribbon.org   -- against proprietary attachments


  
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Bowie Bailey]

On 7/1/2011 12:36 PM, Timothy Murphy wrote:
> Rudi Ahlers wrote:
>
>>> It seems to me that it should be possible
>>> to have a simple, torch-battery operated, system
>>> which will keep the machine alive long enough
>>> to make a graceful exit.
>> A UPS would be your simplest option here since the UPS can send a
>> signal to the OS to shutdown properly.
>>
>> Using a "torch battery" (I presume this is a large torch?) you'll
>> still have the same issue as you have now - when the battery runs flat
>> (i.e. power outage is longer than 10 minutes or so) Linux will still
>> crash uncleanly.
> As will be obvious, I know nothing in this area.
> My thought was just that the machine only requires say 30 seconds of life
> to shutdown properly, and I would have thought
> there was enough capacity in a large torch battery to supply this?
>
> But there seems to be a 100% backing for UPS,
> so I'll look into that.

A UPS is the implementation of your "torch battery" idea.  Remember that
the battery will need a way to convert from DC to the A/C power required
by your machine.  There also needs to be circuitry to switch over to
battery power in the event of an outage.  You also need to make sure the
battery stays charged.  The UPS does all of this for you.  The UPS can
also notify your server in the event of a power outage so it can shut
down cleanly.  If you don't require a long runtime, then you don't need
to get a huge UPS.  APC's website has a calculator that can help you
determine which UPS will work best based on your equipment and desired
runtime.

-- 
Bowie
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Timothy Murphy]

Rudi Ahlers wrote:

>> It seems to me that it should be possible
>> to have a simple, torch-battery operated, system
>> which will keep the machine alive long enough
>> to make a graceful exit.

> A UPS would be your simplest option here since the UPS can send a
> signal to the OS to shutdown properly.
> 
> Using a "torch battery" (I presume this is a large torch?) you'll
> still have the same issue as you have now - when the battery runs flat
> (i.e. power outage is longer than 10 minutes or so) Linux will still
> crash uncleanly.

As will be obvious, I know nothing in this area.
My thought was just that the machine only requires say 30 seconds of life
to shutdown properly, and I would have thought
there was enough capacity in a large torch battery to supply this?

But there seems to be a 100% backing for UPS,
so I'll look into that.

-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Robert Heller]

At Fri, 1 Jul 2011 11:46:40 -0400 CentOS mailing list  wrote:

> 
> centos-boun...@centos.org wrote:
> > On 7/1/2011 10:59 AM, Robert Heller wrote:
> >> 
> >> APC UPSes are supported by apcupsd.  Other brands, not so much.  Some
> >> (read: cheaper models) have their own special protocol and don't
> >> include Linux support.  These solutions are intended for the cheaper
> >> or otherwise 'unsupported' UPSes.  It *sounds* like the OP does not
> >> need something smart and is probably looking for something cheap.
> >> 
> > 
> > And the APC Smart-UPS 750 units are not all that expensive
> > either.  Even the 1500VA units are a lot less expensive then they were
> 5-10
> > years ago.   $250-$300 to protect $2000-$6000 worth of hardware is
> worth
> > it in my book.
> 
> To what extent does a UPS *protect* the hardware?
> Maintaining up-time during brief brown-outs is one thing I expect of a
> UPS,
> Orderly shutdown is another thing I expect of a UPS.
> 
> *protection* of the PC from irregularity in the AC Mains by a UPS,
> however, I question.
> Rather, it seems, any power irregularity that would kill a PC by
> propagating through the PSU will also propagate through the UPS.

A *good* UPS has a surge protector, then a good filtering power supply,
which functions as a battery charger.  Then there is an inverter
(powered by the battery) that generates 'fresh' AC.  'Normal' surges
are soaked up by the input 'battery charger' supply.  A UPS that
decouples the line power from its output by using the inverter all of
the (not just during a power failure) effectively isolates the output
from the the input -- all irregularities in the AC Mains are absorbed
by the battery charger supply.  The battery is very tolerant and does
not need the battery charger circuit to provide a *precise* continious
voltage -- eg dropouts that take the battery charger circuit 'off line'
for miliseconds are not going to affect the battery. Nor will modest
surges (regulation in the battery charger circuit should take care of
larger surges and MOVs on the AC Mains should take care of really large
surges). The inverter will be powered by the battery charger or
battery, depending on which is functioning at any given instant, and
the input to the inverter will be a flat, smooth DC voltage in either
case.

> 
> NO UPS MADE TODAY (according to my reading of the stats on
> advertisements) eats lightning strikes and asks for more.

It is likely that the UPS would die, leaving the computer, etc. untouched.

> 
> So per your experiences and greater technical savvy: What PSU/PC kill
> power irregularities will be stopped by which UPS?

Certainly random 'low-level' surges (typical 'dirty' power as provided
by the power company).  The UPS would also be the front-line 'cannon
fodder' for more massive surges (eg lightning strikes). 

In reality, a *properly* wired building (one that is up to code), will
have effective lightning protection as part of the basic wiring.  A data
center wiring will be even better.

> 
> 
> Insert spiffy .sig here:
> Life is complex: it has both real and imaginary parts.
> Life is not measured by the number of breaths we take, but by the
> moments that take our breath away. 
> 
> 
> //me
> ***
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom
> they are addressed. If you have received this email in error please
> notify the system manager. This footnote also confirms that this
> email message has been swept for the presence of computer viruses.
> www.Hubbell.com - Hubbell Incorporated**
> 
> ___
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
> 
>   
>

-- 
Robert Heller -- 978-544-6933 / hel...@deepsoft.com
Deepwoods Software-- http://www.deepsoft.com/
()  ascii ribbon campaign -- against html e-mail
/\  www.asciiribbon.org   -- against proprietary attachments


   
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Rudi Ahlers]

On Fri, Jul 1, 2011 at 5:46 PM, Brunner, Brian T.
 wrote:
>
> NO UPS MADE TODAY (according to my reading of the stats on
> advertisements) eats lightning strikes and asks for more.
>
> So per your experiences and greater technical savvy: What PSU/PC kill
> power irregularities will be stopped by which UPS?
>
>


Well, the UPS itself normally blows a fuse, or itself gets burnt out,
so you pay a small price to protect a bigger investment



-- 
Kind Regards
Rudi Ahlers
SoftDux

Website: http://www.SoftDux.com
Technical Blog: http://Blog.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[m . roth]

Brunner, Brian T. wrote:
> centos-boun...@centos.org wrote:
>> On 7/1/2011 10:59 AM, Robert Heller wrote:
>>>
>>> APC UPSes are supported by apcupsd.  Other brands, not so much.  Some
>>> (read: cheaper models) have their own special protocol and don't
>>> include Linux support.  These solutions are intended for the cheaper
>>> or otherwise 'unsupported' UPSes.  It *sounds* like the OP does not
>>> need something smart and is probably looking for something cheap.
>>>
>>
>> And the APC Smart-UPS 750 units are not all that expensive
>> either.  Even the 1500VA units are a lot less expensive then they were
> > 5-10 years ago.   $250-$300 to protect $2000-$6000 worth of hardware is
> worth it in my book.
>
> To what extent does a UPS *protect* the hardware?
> Maintaining up-time during brief brown-outs is one thing I expect of a
> UPS,Orderly shutdown is another thing I expect of a UPS.
>
> *protection* of the PC from irregularity in the AC Mains by a UPS,
> however, I question.
> Rather, it seems, any power irregularity that would kill a PC by
> propagating through the PSU will also propagate through the UPS.
>
> NO UPS MADE TODAY (according to my reading of the stats on
> advertisements) eats lightning strikes and asks for more.
>
> So per your experiences and greater technical savvy: What PSU/PC kill
> power irregularities will be stopped by which UPS?

Really? That's what you read in the specs? Here, I thought that good
quality surge protectors would do that, and my UPS does says surge
protection as well as UPS. IIRC, UPSs, and better surge protectors, offer
a multi-thousand dollar warranty if it doesn't stop a large surge and your
system's fried.

I *think* I have one of these,
,
which they say is suitable for SOHO usage... and you notice the "connected
equipment guarantee" (CEG): between $25k USDand $100k USD, depending on
model.

 mark

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[m . roth]

Blake Hudson wrote:
> From: m.r...@5-cent.us
>> Blake Hudson wrote:
>>> From: m.r...@5-cent.us
 Nicolas Thierry-Mieg wrote:
> Colin Coles wrote:
>> On Friday 01 July 2011 12:05, Timothy Murphy wrote:
>>> Any advice or suggestions gratefully received.
>> If you are thinking of the UPS route a caveat: I have several HP
>> servers and most of them will not work on cheap UPS's as they do not
>> produce the pure sine wave modern HP machines require but rather a
>> crude stepped voltage.
> perhaps naively, I'm surprised: doesn't this mean they put crappy
> PSUs
> in those servers?
> I thought decent PSUs were expected to deal with dirty input AC?
 I agree. Esp. since, other than in datacenters, *most* electric power
 is
 pretty crappy.
>>> I would have to disagree. They probably put high efficiency active PFC
>>> power supplies in the servers to save YOU money. You could buy a
>>> cheaper
>>> PSU that will not be as efficient and would thus cost you more in
>>> electric costs and create more heat (which would again cost you more in
>>> AC bills and reduce server density). The active PFC supplies are
>> Except that I expect datacenters to have conditioned power, and so they
>> can cheap out with the servers, with the same expectations. And I would
>> expect consumer-grade systems to not have fancy power units, but ones
>> that
>> won't die on power irregularities from the electric co's.
>> 

> I think you missed the point - While manufacturer's could (and probably
> sometimes do) "cheap out with the servers" power supplies, it is not in
> your best interest (or their's).

Oh, I haven't missed the point - you missed my point, that they will cheap
out - that's in the interest of their stockholders, and their exec's stock
options. Better power supplies, though they actually cost *them* a few
dollars more, are much more expensive options.
>
> More efficient PSUs create less waste heat and draw less power which
> means higher density, more performance, etc. This is more important in
> the server space where the computers are on 24/7 and tightly packed into
> racks. More efficient PSUs cost more upfront than inefficient ones,
> which mean that Dell/HP/etc can probably make a higher profit. In the
> long term, you may be saving $50-100 per server per year on reduced
> electric and associated costs. If you're in a colo with power draw
> restrictions, you may be saving even more.

Yup. As a matter of fact, my own brand new machine here at work just
arrived an hour ago (ah, the smell of fresh plastic outgassing, factory
air from China :((( ), and when I spec'd it out, this was the option:

Precision T3500 CMT Standard PSU, C2 Motherboard [Included in Price]
Precision T3500, CMT, 85 Percent Efficient Power Supply, C2 Motherboard
[add $42.82]

You know that's maybe $5, with the quantities they're buying.

mark

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Brunner, Brian T.]

centos-boun...@centos.org wrote:
> On 7/1/2011 10:59 AM, Robert Heller wrote:
>> 
>> APC UPSes are supported by apcupsd.  Other brands, not so much.  Some
>> (read: cheaper models) have their own special protocol and don't
>> include Linux support.  These solutions are intended for the cheaper
>> or otherwise 'unsupported' UPSes.  It *sounds* like the OP does not
>> need something smart and is probably looking for something cheap.
>> 
> 
> And the APC Smart-UPS 750 units are not all that expensive
> either.  Even the 1500VA units are a lot less expensive then they were
5-10
> years ago.   $250-$300 to protect $2000-$6000 worth of hardware is
worth
> it in my book.

To what extent does a UPS *protect* the hardware?
Maintaining up-time during brief brown-outs is one thing I expect of a
UPS,
Orderly shutdown is another thing I expect of a UPS.

*protection* of the PC from irregularity in the AC Mains by a UPS,
however, I question.
Rather, it seems, any power irregularity that would kill a PC by
propagating through the PSU will also propagate through the UPS.

NO UPS MADE TODAY (according to my reading of the stats on
advertisements) eats lightning strikes and asks for more.

So per your experiences and greater technical savvy: What PSU/PC kill
power irregularities will be stopped by which UPS?


Insert spiffy .sig here:
Life is complex: it has both real and imaginary parts.
Life is not measured by the number of breaths we take, but by the
moments that take our breath away. 


//me
***
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom
they are addressed. If you have received this email in error please
notify the system manager. This footnote also confirms that this
email message has been swept for the presence of computer viruses.
www.Hubbell.com - Hubbell Incorporated**

___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Thomas Harold]

On 7/1/2011 10:59 AM, Robert Heller wrote:
>
> APC UPSes are supported by apcupsd.  Other brands, not so much.  Some
> (read: cheaper models) have their own special protocol and don't
> include Linux support.  These solutions are intended for the cheaper or
> otherwise 'unsupported' UPSes.  It *sounds* like the OP does not need
> something smart and is probably looking for something cheap.
>

And the APC Smart-UPS 750 units are not all that expensive either.  Even 
the 1500VA units are a lot less expensive then they were 5-10 years ago. 
  $250-$300 to protect $2000-$6000 worth of hardware is worth it in my book.

(I prefer the Smart-UPS units for a variety of reasons.  Line filtering, 
voltage regulation, and nice reporting features via apcupsd.  We have 
MRTG polling the apcupsd data regularly and have graphs of line voltage 
/ operating temperature.  There are even variants with the audible alarm 
disabled, which is perfect for a home office where you don't need that 
high powered screech.)
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos

Re: [CentOS] Power-outage

[Blake Hudson]

 Original Message  
Subject: Re: [CentOS] Power-outage
From: m.r...@5-cent.us
To: CentOS mailing list 
Date: Friday, July 01, 2011 9:57:41 AM
> Blake Hudson wrote:
>> From: m.r...@5-cent.us
>>> Nicolas Thierry-Mieg wrote:
>>>> Colin Coles wrote:
>>>>> On Friday 01 July 2011 12:05, Timothy Murphy wrote:
>>>>>> Any advice or suggestions gratefully received.
>>>>> If you are thinking of the UPS route a caveat: I have several HP
>>>>> servers and most of them will not work on cheap UPS's as they do not
>>>>> produce the pure sine wave modern HP machines require but rather a
>>>>> crude stepped voltage.
>>>> perhaps naively, I'm surprised: doesn't this mean they put crappy PSUs
>>>> in those servers?
>>>> I thought decent PSUs were expected to deal with dirty input AC?
>>> I agree. Esp. since, other than in datacenters, *most* electric power is
>>> pretty crappy.
>> I would have to disagree. They probably put high efficiency active PFC
>> power supplies in the servers to save YOU money. You could buy a cheaper
>> PSU that will not be as efficient and would thus cost you more in
>> electric costs and create more heat (which would again cost you more in
>> AC bills and reduce server density). The active PFC supplies are
> Except that I expect datacenters to have conditioned power, and so they
> can cheap out with the servers, with the same expectations. And I would
> expect consumer-grade systems to not have fancy power units, but ones that
> won't die on power irregularities from the electric co's.
> 
> mark
I think you missed the point - While manufacturer's could (and probably
sometimes do) "cheap out with the servers" power supplies, it is not in
your best interest (or their's).

More efficient PSUs create less waste heat and draw less power which
means higher density, more performance, etc. This is more important in
the server space where the computers are on 24/7 and tightly packed into
racks. More efficient PSUs cost more upfront than inefficient ones,
which mean that Dell/HP/etc can probably make a higher profit. In the
long term, you may be saving $50-100 per server per year on reduced
electric and associated costs. If you're in a colo with power draw
restrictions, you may be saving even more.
___
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos