From: Robin Hill <robin@robinhill.me.uk>
To: linux-raid@vger.kernel.org
Subject: Re: when read error ,where do we rewrite?
Date: Fri, 8 Jan 2010 10:03:36 +0000 [thread overview]
Message-ID: <20100108100336.GA21358@cthulhu.home.robinhill.me.uk> (raw)
In-Reply-To: <6c394cc31001072059t2669afa8l5fed42ff77b3c134@mail.gmail.com>
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On Fri Jan 08, 2010 at 12:59:26PM +0800, dong wu wrote:
> In the source code of raid5,when write error,it faulty the disk,not remap
> the block. why do it use "remap the block"?
>
There's two separate error cases - read error and write error.
If the RAID layer gets a read error from the disk, it uses the parity to
recalculate the data and then writes it back to the disk. If the disk
(internally) gets an error when writing this block, it should silently
mark it as faulty and map a spare block in to replace it, writing to
that instead,
If the RAID layer gets a write error from the disk, this indicates that
it's failed to do this remapping, so it marks the disk as faulty.
HTH,
Robin
--
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( ' } | Robin Hill <robin@robinhill.me.uk> |
/ / ) | Little Jim says .... |
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prev parent reply other threads:[~2010-01-08 10:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-07 12:41 when read error ,where do we rewrite? dong wu
2010-01-07 13:18 ` Robin Hill
2010-01-08 4:54 ` dong wu
2010-01-08 4:59 ` dong wu
2010-01-08 6:35 ` Michael Evans
2010-01-08 10:03 ` Robin Hill [this message]
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