From: Matt Garman <matthew.garman@gmail.com>
To: keld@keldix.com
Cc: George Spelvin <linux@horizon.com>, Mdadm <linux-raid@vger.kernel.org>
Subject: Re: Why are reads not balanced across my RAID-1?
Date: Fri, 24 Jan 2014 08:56:02 -0600 [thread overview]
Message-ID: <CAJvUf-BfK-CeLFZ3WmRFbSpjr_x8x1FO7pDX5gmAJyw2RpekxA@mail.gmail.com> (raw)
In-Reply-To: <20140124120448.GA19163@www5.open-std.org>
On Fri, Jan 24, 2014 at 6:04 AM, <keld@keldix.com> wrote:
> The reading is not balanced because it does not make sense to do balanced
> reads for sequential reading. In RAID-1 the disk sectors are consequitive.
> So if you would read one sector from one disk, and the following sector from the other disk,
> then the next read from disk 1 would need to skip a full resolvation of the disk,
> which may cost something like 8 ms. So better read contigously from the same disk, and hope
> for some other IO request that can use disk 2.
Does that rationale hold for SSDs?
next prev parent reply other threads:[~2014-01-24 14:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-24 10:47 Why are reads not balanced across my RAID-1? George Spelvin
2014-01-24 12:04 ` keld
2014-01-24 13:33 ` George Spelvin
2014-01-25 1:48 ` keld
2014-01-24 14:56 ` Matt Garman [this message]
2014-01-24 16:50 ` Mathias Burén
2014-01-24 17:49 ` keld
2014-01-24 18:22 ` Roberto Spadim
2014-01-25 1:18 ` George Spelvin
2014-01-30 20:05 ` Phillip Susi
2014-01-25 17:52 ` Robert L Mathews
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