Date: Mon, 14 Aug 2006 13:03:41 -0400
From: Michael Stone <mstone+postgres@mathom.us>
Subject: Re: Postgresql Performance on an HP DL385 and
In-reply-to: <20060814153841.GF27928@pervasive.com>
To: "Jim C. Nasby" <jnasby@pervasive.com>
Cc: pgsql-performance@postgresql.org
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On Mon, Aug 14, 2006 at 10:38:41AM -0500, Jim C. Nasby wrote:
>Got any data to back that up?

yes. that I'm willing to dig out? no. :)

>The problem with seperate partitions is that it means more head movement
>for the drives. If it's all one partition the pg_xlog data will tend to
>be interspersed with the heap data, meaning less need for head
>repositioning.

The pg_xlog files will tend to be created up at the front of the disk 
and just sit there. Any affect the positioning has one way or the other 
isn't going to be measurable/repeatable. With a write cache for pg_xlog 
the positioning isn't really going to matter anyway, since you don't 
have to wait for a seek to do the write.