On Dec 5, 2006, at 8:54 PM, Greg Smith wrote:
On Tue, 5 Dec 2006, Craig A. James wrote:
I'm not familiar with the inner details of software RAID, but the
only circumstance I can see where things would get corrupted is if
the RAID driver writes a LOT of blocks to one disk of the array
bef
On Tue, 5 Dec 2006, Craig A. James wrote:
I'm not familiar with the inner details of software RAID, but the only
circumstance I can see where things would get corrupted is if the RAID driver
writes a LOT of blocks to one disk of the array before synchronizing the
others...
You're talking abo
On Tue, Dec 05, 2006 at 07:57:43AM -0500, Alex Turner wrote:
The problem I see with software raid is the issue of a battery backed unit:
If the computer loses power, then the 'cache' which is held in system
memory, goes away, and fubars your RAID.
Since the Adaptec doesn't have a BBU, it's a la
Alex Turner wrote:
The problem I see with software raid is the issue of a battery backed
unit: If the computer loses power, then the 'cache' which is held in
system memory, goes away, and fubars your RAID.
I'm not sure I see the difference. If data are cached, they're not written
whether it
The problem I see with software raid is the issue of a battery backed unit:
If the computer loses power, then the 'cache' which is held in system
memory, goes away, and fubars your RAID.
Alex
On 12/5/06, Michael Stone <[EMAIL PROTECTED]> wrote:
On Tue, Dec 05, 2006 at 01:21:38AM -0500, Alex Tu
On Tue, Dec 05, 2006 at 01:21:38AM -0500, Alex Turner wrote:
My other and most important point is that I can't find any solid
recommendations for a SCSI card that can perform optimally in Linux or
*BSD. Off by a factor of 3x is pretty sad IMHO. (and yes, we know the
Adaptec cards suck worse, tha
I agree, that MegaRAID is very stable, and it's very appealing from that
perspective. And two years ago I would have never even mentioned cciss
based cards on this list, because they sucked wind big time, but I believe
some people have started seeing better number from the 6i. 20MB/sec write,
wh
On Mon, 4 Dec 2006, Alex Turner wrote:
People recommend LSI MegaRAID controllers on here regularly, but I have
found that they do not work that well. I have bonnie++ numbers that
show the controller is not performing anywhere near the disk's
saturation level in a simple RAID 1 on RedHat Linux
On Mon, 2006-12-04 at 11:37, Alex Turner wrote:
> The RAID 10 was in there merely for filling in, not really as a
> compare, indeed it would be ludicrous to compare a RAID 1 to a 6 drive
> RAID 10!!
>
> How do I find out if it has version 2 of the driver?
Go to the directory it lives in (on my Fe
On Mon, 2006-12-04 at 11:43, Michael Stone wrote:
> On Mon, Dec 04, 2006 at 12:37:29PM -0500, Alex Turner wrote:
> >This discussion I think is important, as I think it would be useful for this
> >list to have a list of RAID cards that _do_ work well under Linux/BSD for
> >people as recommended hard
On Mon, Dec 04, 2006 at 12:52:46PM -0500, Alex Turner wrote:
http://en.wikipedia.org/wiki/RAID_controller
What is the wikipedia quote supposed to prove? Pray tell, if you
consider RAID==HBA, what would you call a SCSI (e.g.) controller that
has no RAID functionality? If you'd call it an HBA,
http://en.wikipedia.org/wiki/RAID_controller
Alex
On 12/4/06, Michael Stone <[EMAIL PROTECTED]> wrote:
On Mon, Dec 04, 2006 at 12:37:29PM -0500, Alex Turner wrote:
>This discussion I think is important, as I think it would be useful for
this
>list to have a list of RAID cards that _do_ work we
On Mon, Dec 04, 2006 at 12:37:29PM -0500, Alex Turner wrote:
This discussion I think is important, as I think it would be useful for this
list to have a list of RAID cards that _do_ work well under Linux/BSD for
people as recommended hardware for Postgresql. So far, all I can recommend
is what
The RAID 10 was in there merely for filling in, not really as a compare,
indeed it would be ludicrous to compare a RAID 1 to a 6 drive RAID 10!!
How do I find out if it has version 2 of the driver?
This discussion I think is important, as I think it would be useful for this
list to have a list o
On Mon, 2006-12-04 at 10:25, Scott Marlowe wrote:
>
> OTOH, with the choice at my last place of employment being LSI or
> Adaptec, LSI was a much better choice. :)
>
> I'd ask which LSI megaraid you've tested, and what driver was used.
> Does RHEL4 have the megaraid 2 driver?
Just wanted to
On Mon, 2006-12-04 at 01:17, Alex Turner wrote:
> People recommend LSI MegaRAID controllers on here regularly, but I
> have found that they do not work that well. I have bonnie++ numbers
> that show the controller is not performing anywhere near the disk's
> saturation level in a simple RAID 1 on
People recommend LSI MegaRAID controllers on here regularly, but I have
found that they do not work that well. I have bonnie++ numbers that show
the controller is not performing anywhere near the disk's saturation level
in a simple RAID 1 on RedHat Linux EL4 on two seperate machines provided by
t
On Thu, 30 Nov 2006, Carlos H. Reimer wrote:
I would like to discover how much cache is present in
the controller, how can I find this value from Linux?
As far as I know there is no cache on an Adaptec 39320. The write-back
cache Linux was reporting on was the one in the drives, which is 8MB
Carlos H. Reimer wrote:
I´ve taken a look in the /var/log/messages and found some temperature
messages about the disk drives:
Nov 30 11:08:07 totall smartd[1620]: Device: /dev/sda, Temperature changed 2
Celsius to 51 Celsius since last report
Can this temperature influence in the performance?
by day.
Reimer
> -Mensagem original-
> De: Mark Kirkwood [mailto:[EMAIL PROTECTED]
> Enviada em: quinta-feira, 30 de novembro de 2006 23:47
> Para: [EMAIL PROTECTED]
> Cc: pgsql-performance@postgresql.org
> Assunto: Re: [PERFORM] Bad iostat numbers
>
>
> Carlos
> -Mensagem original-
> De: David Boreham [mailto:[EMAIL PROTECTED]
> Enviada em: sexta-feira, 1 de dezembro de 2006 00:25
> Para: [EMAIL PROTECTED]
> Cc: pgsql-performance@postgresql.org
> Assunto: Re: [PERFORM] Bad iostat numbers
>
>
> Carlos H. Reimer wrote:
>
>
David Boreham wrote:
These number look a bit strange. I am wondering if there is a hardware
problem on one of the drives
or on the controller. Check in syslog for messages about disk timeouts
etc. 100% util but 6 writes/s
is just wrong (unless the drive is a 1980's vintage floppy).
Agreed
Carlos H. Reimer wrote:
avg-cpu: %user %nice %system %iowait %idle
50.400.000.501.10 48.00
Device:rrqm/s wrqm/s r/s w/s rsec/s wsec/srkB/swkB/s
avgrq-sz avgqu-sz await svctm %util
sda 0.00 7.80 0.40 6.40 41.60 113.60
Carlos H. Reimer wrote:
While collecting performance data I discovered very bad numbers in the
I/O subsystem and I would like to know if I´m thinking correctly.
Here is a typical iostat -x:
avg-cpu: %user %nice %system %iowait %idle
50.400.000.501.10 48.00
Hi,
I was called to find out why one of our PostgreSQL servers has not a
satisfatory response time. The server has only two SCSI disks configurated
as a RAID1 software.
While collecting performance data I discovered very bad numbers in the I/O
subsystem and I would like to know if I´m thinking co
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