Re: questions about disk configurations - Mailing list pgsql-performance

From eric soroos
Subject Re: questions about disk configurations
Date
Msg-id 88699896.1172681174@[4.42.179.151]
Whole thread Raw
In response to Re: questions about disk configurations  (Josh Berkus <josh@agliodbs.com>)
Responses Re: questions about disk configurations  (Josh Berkus <josh@agliodbs.com>)
Re: questions about disk configurations  ("scott.marlowe" <scott.marlowe@ihs.com>)
List pgsql-performance
>
> Er, no, it's not.  In fact, for a 3-disk config, I reccommend:
>
> Disk 1: OS, swap, system logs
> Disk 2: Data + Indexes
> Disk 3: Transaction Log

What is the accepted way of splitting the data from pg_xlog?

I've been testing some configurations for low budget performance, and I haven't been able to make this help vs. one
disk.(under osx, ymmv) 

I rsync'd the pg_xlog directory to another disk, then set up a symlink pointing from the data/pg_xlog to
/other/disk/pg_xlog. 

I then got tps numbers that were 2/3 of the single ide drive speed. The only explanation I can come up with is that
somethingis seeking to the symlink, then doing the actual write on the other drive.  

I'm going to try this under linux using mount points, but I need to shuffle hardware first.


any ideas?

eric




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