Date: Mon, 02 May 2005 16:23:23 +0300 From: Petri Helenius <pete@he.iki.fi> To: Poul-Henning Kamp <phk@phk.freebsd.dk> 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 Message-ID: <427629CB.6060706@he.iki.fi> In-Reply-To: <17442.1115039706@critter.freebsd.dk> References: <17442.1115039706@critter.freebsd.dk>
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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
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