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Date: Tue, 10 Dec 2002 16:34:42 +0100
From: Jakob Oestergaard <jakob@unthought.net>
To: "Robert L. Harris" <Robert.L.Harris@rdlg.net>,
       Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: Re: RAID5 chunksize?
Message-ID: <20021210153442.GB28095@unthought.net>
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On Tue, Dec 10, 2002 at 10:23:30AM -0500, Robert L. Harris wrote:
> 
> 
> Ok, say I'm building a 4 disk raid5 array.  Performance is going to be
> critical as this system is going to be very IO intensive.  We had to go
> RAID5 though due to filesystem requirements.
> 
> According to the manufacturer the disks have:
> 
>   8Meg DataBuffer
>   10K RPM Rotational speed
>   SCSI Ultra 160
> 
> (Drive is:
> http://www.fel.fujitsu.com/home/product.asp?L=en&PID=248&INFO=fsp)
> 
> What is the ideal Chunksize?  

Measure.

Try 4k, 32k, 128k, and see which is best.

Please post the results to the list  :)

It is important that you benchmark not with tiotest or bonnie, but with
the actual applications that need to use this server.

-- 
................................................................
:   jakob@unthought.net   : And I see the elder races,         :
:.........................: putrid forms of man                :
:   Jakob ?stergaard      : See him rise and claim the earth,  :
:        OZ9ABN           : his downfall is at hand.           :
:.........................:............{Konkhra}...............:
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