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From: Greg Smith <greg@2ndquadrant.com>
To: Greg Spiegelberg <gspiegelberg@gmail.com>
Cc: Yeb Havinga <yebhavinga@gmail.com>
Cc: Matthew Wakeling <matthew@flymine.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Testing Sandforce SSD
Date: Mon, 26 Jul 2010 14:40:43 -0400
Message-ID: <4C4DD6AB.6000805@2ndquadrant.com> (raw)
In-Reply-To: <AANLkTikSLLcUKdD=mZhN4MnSyUAvmgGqnmPCFKdmXbAJ@mail.gmail.com>
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Greg Spiegelberg wrote:
> Speaking of the layers in-between, has this test been done with the 
> ext3 journal on a different device?  Maybe the purpose is wrong for 
> the SSD.  Use the SSD for the ext3 journal and the spindled drives for 
> filesystem?  

The main disk bottleneck on PostgreSQL databases are the random seeks 
for reading and writing to the main data blocks.  The journal 
information is practically noise in comparison--it barely matters 
because it's so much less difficult to keep up with.  This is why I 
don't really find ext2 interesting either.

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

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