Find !
Dell CERC SATA RAID 2 PCI SATA 6ch
Running lspci -v:
03:09.0 RAID bus controller: Adaptec AAC-RAID (rev 01)
Subsystem: Dell CERC SATA RAID 2 PCI SATA 6ch (DellCorsair)
Flags: bus master, 66MHz, slow devsel, latency 32, IRQ 209
Memory at f8000000 (32-bit, prefetchable) [size=64M]
Expansion ROM at fe800000 [disabled] [size=32K]
Capabilities: [80] Power Management version 2
Any consideration looking at iostat output ?
Cheers and thanks to all!
ste
On Wed, Jan 7, 2009 at 10:31 PM, Scott Marlowe
<scott.marlowe@gmail.com> wrote:
On Wed, Jan 7, 2009 at 2:02 PM, Stefano Nichele
> On Tue, Jan 6, 2009 at 7:45 PM, Scott Marlowe <
scott.marlowe@gmail.com>
> wrote:
>>
>> I concur with Merlin you're I/O bound.
>>
>> Adding to his post, what RAID controller are you running, does it have
>> cache, does the cache have battery backup, is the cache set to write
>> back or write through?
>
>
> At the moment I don't have such information. It's a "standard" RAID
> controller coming with a DELL server. Is there any information I can have
> asking to the SO ?
controllers are pretty much either total crap, or mediocre at best.
The latest one, the Perc 6 series are squarely in the same performance
realm as a 4 or 5 year old LSI megaraid. The perc 5 series and before
are total performance dogs. The really bad news is that you can't
generally plug in a real RAID controller on a Dell. We put an Areca
168-LP PCI-x8 in one of our 1950s and it wouldn't even turn on, got a
CPU Error.
Dells are fine for web servers and such. For database servers they're
a total loss. The best you can do with one is to put a generic SCSI
card in it and connect to an external array with its own controller.
We have a perc6e and a perc5e in two different servers, and no matter
how we configure them, we can't get even 1/10th the performance of an
Areca controller with the same number of drives on another machine of
the same basic class as the 1950s.
>> Also, what do you get for this (need contrib module pgbench installed)
>>
>> pgbench -i -s 100
>> pgbench -c 50 -n 10000
>>
>> ? Specifically transactions per second?
>
> I'll run pgbench in the next days.
Cool. That pgbench is a "best case scenario" benchmark. Lots of
small transactions on a db that should fit into memory. If you can't
pull off a decent number there (at least a few hundred tps) then can't
expect better performance from real world usage.
Oh, and that should be:
pgbench -c 50 -t 10000
not -n... not enough sleep I guess.
