Message-ID: <469D3A93.8010701@drivefaster.net>
Date: Tue, 17 Jul 2007 15:54:27 -0600
From: Dan Harris <fbsd@drivefaster.net>
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To: PostgreSQL Performance <pgsql-performance@postgresql.org>
Subject: Re: importance of fast disks with pg
References: <469D382E.6030603@ifi.uio.no>
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Thomas Finneid wrote:
> Hi
> 
> During the somes I did I noticed that it does not necessarily seem to be 
> true that one needs the fastest disks to have a pg system that is fast.
> 
> It seems to me that its more important to:
> - choose the correct methods to use for the operation
> - tune the pg memory settings
> - tune/disable pg xlog/wal etc
> 
> It also seems to me that fast disks are more important for db systems of 
> the OLTP type applications with real concurrency of both readers and 
> writes across many, possibly larger, tables etc.
> 
> Are the above statements close to having any truth in them?
> 
> regards
> 
> thomas

I'd say that "it depends".  We run an OLAP workload on 350+ gigs of database on 
a system with 64GB of RAM.  I can tell you for certain that fetching non-cached 
data is very sensitive to disk throughput!

Different types of workloads will find different bottlenecks in the system..

-Dan