From: Brendan Conoboy <blc@redhat.com>
To: Janek Kozicki <janek_listy@wp.pl>
Cc: linux-raid@vger.kernel.org
Subject: Re: 2x6 or 3x4 raid10 arrays ?
Date: Thu, 28 Feb 2008 14:04:52 -0700 [thread overview]
Message-ID: <47C721F4.1080506@redhat.com> (raw)
In-Reply-To: <20080228215339.6674f29d@absurd>
Janek Kozicki wrote:
> * two 6 disks raid10 arrays : theoretical max speed 6 times single disc
> * three 4 disks raid10 arrays : theoretical max speed 4 times single disc
> * single raid10 far=2 : theoretical max speed 12 times single disc (!)
>
> isn't that true?
If speed is raw throughput then that's approximately right. Unless
you're streaming huge piles of data, that sort of speed isn't what you
need to tune for, though. Look at it this way:
two 6 disk raid 10 arrays : theoretical max seeks per operation: 6 times
the seeks of a single disk
three 4 disk raid 10 arrays: theoretical max seeks per operation: 4
times the seeks of a single disk
one 12 disk raid 10 arrays: theoretical max seeks per operation: 12
times the seeks of a single disk!
Seeks are bad. You have to tune for your workload.
--
Brendan Conoboy / Red Hat, Inc. / blc@redhat.com
next prev parent reply other threads:[~2008-02-28 21:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-28 10:45 2x6 or 3x4 raid10 arrays ? Franck Routier
2008-02-28 11:22 ` Tim Southerwood
2008-02-28 16:54 ` Brendan Conoboy
2008-02-28 18:25 ` Janek Kozicki
2008-02-28 20:53 ` Janek Kozicki
2008-02-28 21:04 ` Brendan Conoboy [this message]
2008-03-01 20:07 ` Bill Davidsen
2008-03-01 20:55 ` Keld Jørn Simonsen
2008-02-28 22:36 ` Nat Makarevitch
2008-03-01 20:40 ` Keld Jørn Simonsen
2008-03-01 21:10 ` Keld Jørn Simonsen
2008-03-01 22:05 ` Nat Makarevitch
2008-03-02 0:30 ` Keld Jørn Simonsen
2008-03-02 9:00 ` Nat Makarevitch
2008-03-01 20:18 ` Bill Davidsen
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