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Date:      Tue, 3 May 2005 13:45:30 +0200 (CEST)
From:      kama <kama@pvp.se>
To:        Poul-Henning Kamp <phk@phk.freebsd.dk>
Cc:        =?ISO-8859-15?Q?=22Arne_=5C=22W=F6rner=5C=22=22?= <arne_woerner@yahoo.com>
Subject:   Re: Very low disk performance on 5.x 
Message-ID:  <20050503134451.P22614@ns1.as.pvp.se>
In-Reply-To: <17442.1115039706@critter.freebsd.dk>
References:  <17442.1115039706@critter.freebsd.dk>

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On Mon, 2 May 2005, 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 system is setup with RAID 1+0. So its not a RAID5 issue...



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