Message-ID: <4DDD81BB.4080801@catalyst.net.nz>
Date: Thu, 26 May 2011 10:24:59 +1200
From: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
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To: =?UTF-8?B?R3J6ZWdvcnogSmHFm2tpZXdpY3o=?= <gryzman@gmail.com>
CC: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: serveRAID M5014 SAS
References: <BANLkTi=fE2YCS0Lra42ei1hFrKqXdVk2jA@mail.gmail.com>
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On 25/05/11 19:33, Grzegorz Jaśkiewicz wrote:
> Does anyone here have any bad experiences with the RAID card in subject ?
> This is in an IBM server, with 2.5" 10k drives.
>
> But we seem to observe its poor performance in other configurations as
> well (with different drives, different settings) in comparison with -
> say, what dell provides.
>
>
>

Interestingly enough, I've been benchmarking a M5015 SAS, with the 
optional wee cable for enabling the battery backup for the 512MB of 
cache. With a 6 disk raid 10 + 2 disk raid 1 - with the array settings 
NORA+DIRECT, and writeback enabled we're seeing quite good pgbench 
performance (12 cores + 48G ram, Ubuntu 10.04 with xfs):

scale 2500 db with 48 clients, 10 minute runs: 2300 tps
scale   500 db with 24 clients, 10 minute runs: 6050 tps

I did notice that the sequential performance was quite lackluster (using 
bonnie) - but are not too concerned about that for the use case (could 
probably fix using blockdev --setra).

I'm guessing that even tho your M5014 card comes with less ram (256M I 
think), if you can enable the battery backup and cache writes it should 
be quite good. Also I think the amount of ram on the card is upgradable 
(4G is the max for the M5105 I *think* - can't find the right doc to 
check this ATM sorry).

Cheers

Mark