From: Asdo <asdo@shiftmail.org>
To: Goswin von Brederlow <goswin-v-b@web.de>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: Question about raid robustness when disk fails
Date: Wed, 27 Jan 2010 11:43:56 +0100 [thread overview]
Message-ID: <4B6018EC.7090805@shiftmail.org> (raw)
In-Reply-To: <87wrz3zvwu.fsf@frosties.localdomain>
Goswin von Brederlow wrote:
>> Is it possible to cancel a SATA/SCSI command that is being executed by
>> the drive?
>> (it's probably feasible only with NCQ disabled anyway, but it's easy
>> to disable NCQ)
>>
>
> Do you want to do that? I would rather have the drive keep trying and
> return an error if it can't read so the raid layer rewrites the blocks
> causing it to be remapped. I do not want to wait for that but I want it
> to happen.
>
So you want that to happen in the background?
Not that much benefit for that to happen in the background, imho.
Why not just having an error returned after a timeout, and normal MD
read-error-recovery procedure kicking in? (recomputation from parity and
rewrite of the damaged block)
>> It's a pity we have to rely on TLER, this narrows the choice of drives
>> a lot...
>>
>
> I don't. I just acknowledge the limitation and accept the downtime
The time might be so long that MD or the controller can drop the entire
drive.
It didn't happen to me but I think I read something like this on this ML...
> to
> find and remove a broken but not properly failed disk. I use raid so I
> don't loose my data when a disk fails, not primarily for availability.
> So far I had one case in 10 years where a failing disk took down my
> system.
>
next prev parent reply other threads:[~2010-01-27 10:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-08 17:39 Question about raid robustness when disk fails Tim Bock
2010-01-22 16:32 ` Goswin von Brederlow
2010-01-25 16:22 ` Tim Bock
2010-01-25 17:51 ` Goswin von Brederlow
2010-01-25 18:12 ` Michał Sawicz
2010-01-26 7:29 ` Goswin von Brederlow
2010-01-27 0:19 ` Ryan Wagoner
2010-01-27 4:22 ` Michael Evans
2010-01-27 9:04 ` Goswin von Brederlow
2010-01-27 9:22 ` Asdo
2010-01-27 10:25 ` Goswin von Brederlow
2010-01-27 10:43 ` Asdo [this message]
2010-01-27 15:34 ` Goswin von Brederlow
2010-01-28 11:52 ` Michael Evans
2010-01-27 15:15 ` Tim Bock
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