On 7/1/11, Les Mikesell lesmikes...@gmail.com wrote:
The principle is the same but the way to control it would be different.
Spamassassin is a perl program that uses a lot of memory and takes a
lot of resources to start up. If you run a lot of copies at once,
expect the machine to crawl or
Although it would really be interesting to me to see scheduler settings that
would indeed allow something of a 'privileged' ssh or an OOB console that
would be responsive even under a punishing load with lots of swapping, which
is what the OP originally asked about.
I'd be interested to
Although it would really be interesting to me to see scheduler settings that
would indeed allow something of a 'privileged' ssh or an OOB console that
would be responsive even under a punishing load with lots of swapping, which
is what the OP originally asked about.
I should add, we have
Am 30.06.2011 08:36, schrieb Steve Barnes:
Although it would really be interesting to me to see scheduler settings that
would indeed allow something of a 'privileged' ssh or an OOB console that
would be responsive even under a punishing load with lots of swapping, which
is what the OP
Robert Heller wrote:
If the machine is a public-facing smtp server, I would look first to see
if you are getting the problem I was having. Maybe looking at the
maillog to see if the volume of incoming mail is just overwhelming the
system. In which case you need to do things to keep sendmail
Steve Barnes wrote:
I'd be interested to hear thoughts on this. We have a small 1U test server
with 2 entry-level SATA drives that was brought to its knees twice this week
by an overzealous Java process. Load averages were up around 60+ and as a
result, SSH access would timeout. I don't
Steve Barnes wrote:
[...]
Or maybe having that core root tree on separate HDD and separate HDD
controller.
Unfortunately, all this does not matter at all.
The problem is: sshd is swapped out and the system needs to swap-out
something else first, before it can take sshd back in.
2011/6/30 rai...@ultra-secure.de:
Steve Barnes wrote:
[...]
Or maybe having that core root tree on separate HDD and separate HDD
controller.
Unfortunately, all this does not matter at all.
The problem is: sshd is swapped out and the system needs to swap-out
something else first,
On 6/30/11, Devin Reade g...@gno.org wrote:
I don't recall you mentioning which VM solution you're using.
KVM :)
Some problematic areas that I've seen when using VMs:
+ memory ballooning sometimes causes problems (I've not actually seen
it, but I've seen various warnings about having it
On 6/30/11, rai...@ultra-secure.de rai...@ultra-secure.de wrote:
Unfortunately, all this does not matter at all.
The problem is: sshd is swapped out and the system needs to swap-out
something else first, before it can take sshd back in.
There appears to be some functions available to programs
On 6/30/11, Simon Matter simon.mat...@invoca.ch wrote:
Hm, I thought the problem was I/O, not memory? If memory is not the
problem then it has nothing to do with swapping (more correctly paging).
After looking through the various replies here and rechecking whatever
logs I managed to get, it
On 6/30/11 6:11 AM, Emmanuel Noobadmin wrote:
On 6/30/11, Simon Mattersimon.mat...@invoca.ch wrote:
Hm, I thought the problem was I/O, not memory? If memory is not the
problem then it has nothing to do with swapping (more correctly paging).
After looking through the various replies here and
On 06/29/11 14:50, Emmanuel Noobadmin wrote:
I was having problems with the same server locking up to the point I
can't even get in via SSH.
investigate instead of band-aiding...
1) syslog to a remote host.
remote syslogging rarely stops when the system is disk/iowait bound.
2) log
On Thu, 30 Jun 2011, rai...@ultra-secure.de wrote:
Steve Barnes wrote:
[...]
Or maybe having that core root tree on separate HDD and separate HDD
controller.
Unfortunately, all this does not matter at all.
The problem is: sshd is swapped out and the system needs to swap-out
something
On Thu, Jun 30, 2011 at 4:38 AM, Alexander Dalloz ad+li...@uni-x.orgwrote:
Am 30.06.2011 08:36, schrieb Steve Barnes:
Although it would really be interesting to me to see scheduler settings
that would indeed allow something of a 'privileged' ssh or an OOB console
that would be responsive
On 6/30/11, Les Mikesell lesmikes...@gmail.com wrote:
Again, fixable by not sharing the disk the guest uses with the disk the host
needs to load programs from... The disk head is always going to be in the
wrong place.
Well, let's just say my original recommendation specifications for
this
On 6/30/2011 12:39 PM, Emmanuel Noobadmin wrote:
But, odds are that the source of the problem is starting too many mail
delivery programs, especially if they, or the user's local procmail, starts a
spamassassin instance per message. Look at the mail logs for a problem time
to see if you had
On 6/30/2011 12:39 PM, Emmanuel Noobadmin wrote:
Right now it doesn't look like an mail run, more like a httpd run
because it's starting to look like a large number of httpd threads was
spawned just before that.
Oh, one other thing... Do the web programs using mysql for anything?
I've seen
At Fri, 1 Jul 2011 01:39:19 +0800 CentOS mailing list centos@centos.org wrote:
On 6/30/11, Les Mikesell lesmikes...@gmail.com wrote:
Again, fixable by not sharing the disk the guest uses with the disk the host
needs to load programs from... The disk head is always going to be in the
On 6/30/2011 4:53 PM, Robert Heller wrote:
Right now it doesn't look like an mail run, more like a httpd run
because it's starting to look like a large number of httpd threads was
spawned just before that.
OK, there are probably settings for Apache to run fewer threads.
Probably better have
Am 29.06.2011 um 21:50 schrieb Emmanuel Noobadmin:
Since I'm not the only person who face problems trying to remotely
access a locked up server, surely somebody must had come up with a
solution that didn't involve somebody/something hitting the power
button?
Yes, it's called out of band
Am 29.06.2011 um 21:50 schrieb Emmanuel Noobadmin:
Since I'm not the only person who face problems trying to remotely
access a locked up server, surely somebody must had come up with a
solution that didn't involve somebody/something hitting the power
button?
Yes, it's called out of
On 6/30/11, Rainer Duffner rai...@ultra-secure.de wrote:
Yes, it's called out of band management.
Have dial-in access to IPMI/iLO interfaces or just an APC remote
controlled power-switch to power-off the server.
I don't want to reboot the server everytime something like that
happens. I'll
Am 29.06.2011 um 22:08 schrieb Max Pyziur:
Am 29.06.2011 um 21:50 schrieb Emmanuel Noobadmin:
Since I'm not the only person who face problems trying to remotely
access a locked up server, surely somebody must had come up with a
solution that didn't involve somebody/something hitting the
Am 29.06.2011 um 22:15 schrieb Emmanuel Noobadmin:
On 6/30/11, Rainer Duffner rai...@ultra-secure.de wrote:
Yes, it's called out of band management.
Have dial-in access to IPMI/iLO interfaces or just an APC remote
controlled power-switch to power-off the server.
I don't want to reboot the
On Wed, Jun 29, 2011 at 4:50 PM, Emmanuel Noobadmin
centos.ad...@gmail.comwrote:
I was having problems with the same server locking up to the point I
can't even get in via SSH. I've already used HTB/TC to reserve
bandwidth for my SSH port but the problem now isn't an attack on the
bandwidth.
On 6/30/11, Rainer Duffner rai...@ultra-secure.de wrote:
If it's a server that actually deserves that name, it should have IPMI
on board.
Problem is some of us work for budget constraints customers and define
server by purpose and not specifications. So very often they buy
servers based on
On Wed, Jun 29, 2011 at 4:15 PM, Emmanuel Noobadmin
centos.ad...@gmail.com wrote:
On 6/30/11, Rainer Duffner rai...@ultra-secure.de wrote:
Yes, it's called out of band management.
Have dial-in access to IPMI/iLO interfaces or just an APC remote
controlled power-switch to power-off the server.
On 6/29/2011 3:26 PM, Emmanuel Noobadmin wrote:
On 6/30/11, Rainer Duffnerrai...@ultra-secure.de wrote:
If it's a server that actually deserves that name, it should have IPMI
on board.
Problem is some of us work for budget constraints customers and define
server by purpose and not
At Wed, 29 Jun 2011 16:08:02 -0400 (EDT) CentOS mailing list
centos@centos.org wrote:
Am 29.06.2011 um 21:50 schrieb Emmanuel Noobadmin:
Since I'm not the only person who face problems trying to remotely
access a locked up server, surely somebody must had come up with a
solution
Am 29.06.2011 um 22:26 schrieb Emmanuel Noobadmin:
On 6/30/11, Rainer Duffner rai...@ultra-secure.de wrote:
If it's a server that actually deserves that name, it should have
IPMI
on board.
Problem is some of us work for budget constraints customers and define
server by purpose and not
On Thu, Jun 30, 2011 at 03:50:30AM +0800, Emmanuel Noobadmin wrote:
I was having problems with the same server locking up to the point I
can't even get in via SSH. I've already used HTB/TC to reserve
bandwidth for my SSH port but the problem now isn't an attack on the
bandwidth. So I'm trying
On 6/29/2011 3:43 PM, Rainer Duffner wrote:
Virtualization is an option, but the trouble is: if the server is I/O-
constrained anyway, virtualization won't help.
Everything will just be even slower.
That's sort-of true, but you don't have to manage the host through the
same interface the
On Wed, 29 Jun 2011, Keith Keller wrote:
In addition to the suggestions already made, one possibility is to
attach a serial console or IP KVM. Logging in may still be awful,
but at least you won't have to go through sshd. I've been able to
log in through a serial getty when sshd was not
Les Mikesell wrote:
You can buy add-on PCI-cards for OOB-management, though.
Thanks for the information, although unless they are really cheap...
The seriously on-the-cheap approach is to run a few virtual servers on
hardware slightly better than one of the individual servers would need.
On 6/30/11, Les Mikesell lesmikes...@gmail.com wrote:
The seriously on-the-cheap approach is to run a few virtual servers on
hardware slightly better than one of the individual servers would need.
Actually THAT is the fundamental problem ;)
The physical server is frankly much more powerful than
On 6/30/11, Paul Heinlein heinl...@madboa.com wrote:
I actually relied for a while on the last choice. I had a remotely
accessible root shell that never logged out. When things got sluggish,
I was able to /bin/kill to my heart's content. It wasn't a pretty
solution, but it kept me running
On Wed, Jun 29, 2011 at 5:57 PM, Emmanuel Noobadmin
centos.ad...@gmail.comwrote:
On 6/30/11, Giovanni Tirloni gtirl...@sysdroid.com wrote:
I would approach this issue from another perspective: who's locking up
the
server (as in eating all resources) and how to stop/constrain it. You can
On 6/30/11, Robert Heller hel...@deepsoft.com wrote:
If the problem is excessive load because Sendmail / Mimedefang / spamd /
etc. is too busy handling tons of mail/spam being dumped on your server, you
might want to look at these sendmail options:
Mail was my first suspect because I had
On 6/29/2011 4:04 PM, Emmanuel Noobadmin wrote:
On 6/30/11, Les Mikeselllesmikes...@gmail.com wrote:
The seriously on-the-cheap approach is to run a few virtual servers on
hardware slightly better than one of the individual servers would need.
Actually THAT is the fundamental problem ;)
The
On Wednesday, June 29, 2011 04:43:09 PM Rainer Duffner wrote:
Virtualization is an option, but the trouble is: if the server is I/O-
constrained anyway, virtualization won't help.
Everything will just be even slower.
That depends. More expensive servers that would be suitable for
Am 29.06.2011 um 23:17 schrieb Lamar Owen:
On Wednesday, June 29, 2011 04:43:09 PM Rainer Duffner wrote:
Virtualization is an option, but the trouble is: if the server is I/
O-
constrained anyway, virtualization won't help.
Everything will just be even slower.
That depends. More
Les Mikesell wrote:
On 6/29/2011 4:04 PM, Emmanuel Noobadmin wrote:
On 6/30/11, Les Mikeselllesmikes...@gmail.com wrote:
The seriously on-the-cheap approach is to run a few virtual servers on
hardware slightly better than one of the individual servers would need.
Actually THAT is the
On 6/29/2011 4:12 PM, Emmanuel Noobadmin wrote:
On 6/30/11, Robert Hellerhel...@deepsoft.com wrote:
If the problem is excessive load because Sendmail / Mimedefang / spamd /
etc. is too busy handling tons of mail/spam being dumped on your server, you
might want to look at these sendmail
On Thu, 30 Jun 2011, Emmanuel Noobadmin wrote:
On 6/30/11, Paul Heinlein heinl...@madboa.com wrote:
I actually relied for a while on the last choice. I had a remotely
accessible root shell that never logged out. When things got
sluggish, I was able to /bin/kill to my heart's content. It
On 6/30/11, Giovanni Tirloni gtirl...@sysdroid.com wrote:
Linux includes I/O in how it calculates the load average so you're not
measuring CPU alone.
On the host, it's expected, I've got two qemu-kvm process loading up
100% cpu. Within the guest VM, top looks like this, high load but low
cpu %.
On 6/30/11, m.r...@5-cent.us m.r...@5-cent.us wrote:
Here's another one, that I got from another admin talking to VMware: watch
out just how many virtual CPUs you assign to each VM. If you've assigned
4, it is actually going to sit there waiting until it gets 4 virtual CPUs.
As of '09, VMware
On 6/29/2011 4:22 PM, m.r...@5-cent.us wrote:
Here's another one, that I got from another admin talking to VMware: watch
out just how many virtual CPUs you assign to each VM. If you've assigned
4, it is actually going to sit there waiting until it gets 4 virtual CPUs.
As of '09, VMware was
On Wed, Jun 29, 2011 at 5:22 PM, m.r...@5-cent.us wrote:
Les Mikesell wrote:
On 6/29/2011 4:04 PM, Emmanuel Noobadmin wrote:
On 6/30/11, Les Mikeselllesmikes...@gmail.com wrote:
The seriously on-the-cheap approach is to run a few virtual servers on
hardware slightly better than one of the
On 6/30/11, Les Mikesell lesmikes...@gmail.com wrote:
OK, but without knowing the cause, you already know the cure. Make the
virtual servers not share physical disks - they will always want a
single head to be in different places at the same time.
Same old problem: budget :D
Also, I expect
Brian Mathis wrote:
On Wed, Jun 29, 2011 at 5:22 PM, m.r...@5-cent.us wrote:
snip
Here's another one, that I got from another admin talking to VMware:
watch out just how many virtual CPUs you assign to each VM. If you've
assigned 4, it is actually going to sit there waiting until it gets 4
--On Thursday, June 30, 2011 04:15:07 AM +0800 Emmanuel Noobadmin
centos.ad...@gmail.com wrote:
Would ILO work on a server that's unresponsive due to heavy load?
ILO or any other OOB solution gives you the functionality of sitting
at the console. So if the problem is one that would cause the
On 6/29/2011 4:47 PM, Emmanuel Noobadmin wrote:
OK, but without knowing the cause, you already know the cure. Make the
virtual servers not share physical disks - they will always want a
single head to be in different places at the same time.
Same old problem: budget :D
If an extra SATA
At Thu, 30 Jun 2011 05:12:12 +0800 CentOS mailing list centos@centos.org
wrote:
On 6/30/11, Robert Heller hel...@deepsoft.com wrote:
If the problem is excessive load because Sendmail / Mimedefang / spamd /
etc. is too busy handling tons of mail/spam being dumped on your server, you
At Thu, 30 Jun 2011 05:31:05 +0800 CentOS mailing list centos@centos.org
wrote:
On 6/30/11, Giovanni Tirloni gtirl...@sysdroid.com wrote:
Linux includes I/O in how it calculates the load average so you're not
measuring CPU alone.
On the host, it's expected, I've got two qemu-kvm
On Wednesday, June 29, 2011 05:20:26 PM Rainer Duffner wrote:
Am 29.06.2011 um 23:17 schrieb Lamar Owen:
More expensive servers that would be suitable for
virtualization host use also tend to have better I/O subsystems and
faster disks. Relative to a 'cheap' system with much poorer
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