Date: Thu, 11 Sep 2008 13:07:26 -0400
From: Andrew Sullivan <ajs@commandprompt.com>
To: pgsql-performance@postgresql.org
Subject: Re: Choosing a filesystem
Message-ID: <20080911170725.GL1008@commandprompt.com>
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On Thu, Sep 11, 2008 at 06:29:36PM +0200, Laszlo Nagy wrote:

> The expert told me to use RAID 5 but I'm hesitating. I think that RAID 1+0 
> would be much faster, and I/O performance is what I really need.

I think you're right.  I think it's a big mistake to use RAID 5 in a
database server where you're hoping for reasonable write performance.
In theory RAID 5 ought to be fast for reads, but I've never seen it
work that way.

> I would like to put the WAL file on the SAS disks to improve performance, 
> and create one big RAID 1+0 disk for the data directory. But maybe I'm 
> completely wrong. Can you please advise how to create logical partitions? 

I would listen to yourself before you listen to the expert.  You sound
right to me :)

A


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Andrew Sullivan
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