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Date: Mon, 02 May 2005 16:23:23 +0300
From: Petri Helenius <pete@he.iki.fi>
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To: Poul-Henning Kamp <phk@phk.freebsd.dk>
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cc: Robert Watson <rwatson@freebsd.org>
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cc: Eric Anderson <anderson@centtech.com>
cc: =?ISO-8859-1?Q?=22Arne_=5C=22W=F6rner=5C=22=22?= <arne_woerner@yahoo.com>
Subject: Re: Very low disk performance on 5.x
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Poul-Henning Kamp wrote:

>In message <427626DC.5030702@centtech.com>, Eric Anderson writes:
>
>  
>
>>Don't mean to be terse here, but I'm talking about the same test done an 
>>two different RAID5 configurations, with different disks, and not just 
>>me - other users in this very thread see the same issue..
>>    
>>
>
>Uhm, if you are using RAID5 and your requests are not aligned and
>sized after the RAID5 you should *expect* read performance to be poor.
>
>If you your request ends up accessing two different blocks even just
>once per stripe, this totally kills performance.
>
>
>  
>
My tests were using RAID10 and just striping. (RAID0 might be the right 
name for it)

Pete