From: Phil Turmel <philip@turmel.org>
To: "Michał Sawicz" <michal@sawicz.net>
Cc: linux-raid@vger.kernel.org
Subject: Re: Help with data recovery - RAID6 with 2 failed drives and another with broken sectors
Date: Sun, 06 Oct 2013 18:15:22 -0400 [thread overview]
Message-ID: <5251E0FA.2030206@turmel.org> (raw)
In-Reply-To: <5251DFF9.4050708@sawicz.net>
On 10/06/2013 06:11 PM, Michał Sawicz wrote:
> On 06.10.2013 23:44, Phil Turmel wrote:
>> The answer is*NO*. That is not expected. But it does happen with
>> timeout mismatches, and the double failure you experienced is a common
>> result of error correction timeout mismatch. Timeout mismatch is where
>> your drives are internally trying to retry reading a bad sector long
>> after the OS has given up. It is always associated with consumer-grade
>> hard drives in raid arrays.
>
> Right, I knew that consumer HDDs did that, but didn't expect this to
> cause such mayhem. So the take out for me for this is: as soon as you
> see bad blocks on the drive, fail it, otherwise the whole array will
> probably get kicked out sooner or later. Or try and manually force the
> drive to reallocate, and then do a scrub.
No, just fix the timeouts. Otherwise, you'll be kicking drives out
*way* more often than you think.
Do check your smartctl reports for actual relocations, though. In my
experience, once you pass single digits, further failures are rapid.
>> You might want to search the list archives for various combinations of
>> "error recovery", "scterc", "URE" and "timeout mismatch" for a full
>> description of the problem and the recommended ways to avoid it.
>
> Thanks, will do.
Phil
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next prev parent reply other threads:[~2013-10-06 22:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 23:23 Help with data recovery - RAID6 with 2 failed drives and another with broken sectors Michał Sawicz
2013-10-01 19:24 ` Michał Sawicz
2013-10-06 21:44 ` Phil Turmel
2013-10-06 22:11 ` Michał Sawicz
2013-10-06 22:15 ` Phil Turmel [this message]
2013-10-06 22:56 ` Michał Sawicz
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