Message-ID: <4C2B4C09.4030500@2ndquadrant.com>
Date: Wed, 30 Jun 2010 14:52:09 +0100
From: Greg Smith <greg@2ndquadrant.com>
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To: Samuel Gendler <sgendler@ideasculptor.com>
CC: pgsql-performance@postgresql.org
Subject: Re: ideal storage configuration
References: <AANLkTilH3dqomgsQtg3JJJbmyA4HAWB18CDBkFaohOG8@mail.gmail.com>
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Samuel Gendler wrote:
> 6 internal drives on battery backed raid (I don't know what RAID level
> - is there a way to discover this?), all in a single filesystem, so
> WAL and data are on the same filesystem.  I don't believe that we are
> taking advantage of the battery backed controller, since I only see
> this in /etc/fstab:
>
> UUID=12dcd71d-8aec-4253-815c-b4883195eeb8 /                       ext3
>    defaults        1 1
>   

That doesn't tell you anything about whether the card's write cache is 
being used or not.  What you need to do is install the monitoring tools 
provided by the manufacturer of the card, which will let you check both 
the RAID level and how the cache is setup.  I can't give any more 
specific instructions because you left out a vital piece of system 
information:  what RAID card you actually have.

-- 
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us