Date: Tue, 20 Sep 2005 05:41:09 -0400
From: Michael Stone <mstone+postgres@mathom.us>
Subject: Re: RAID Stripe size
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	<432F8F1B.7030901@arbash-meinel.com> <432FBF8D.5010501@canaan.co.il>
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On Tue, Sep 20, 2005 at 10:51:41AM +0300, Michael Ben-Nes wrote:
>I must admit im a bit amazed how such important parameter is so 
>ambiguous. an optimal strip size can improve the performance of the db 
>significantly. 

It's configuration dependent. IME, it has an insignificant effect. If
anything, changing it from the vendor default may make performance worse
(maybe the firmware on the array is tuned for a particular size?)

>I bet that the difference in performance between a poor stripe setting
>to an optimal one is more important then how much RAM or CPU you have.

I'll take that bet, because I've benched it. If something so trivial
(and completely free) was the single biggest factor in performance, do
you really think it would be an undiscovered secret?

>I hope to run some tests soon thugh i have limited time on the
>production server to do such tests.

Well, benchmarking your data on your hardware is the first thing you
should do, not something you should try to cram in late in the game. You
can't get a valid answer to a "what's the best configuration" question
until you've tested some configurations.

Mike Stone