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From: Rogier Wolff <R.E.Wolff@BitWizard.nl>
To: Robert Hancock <hancockr@shaw.ca>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Driver retries disk errors.
Date: Thu, 2 Sep 2004 01:04:47 +0200	[thread overview]
Message-ID: <20040901230447.GB28809@bitwizard.nl> (raw)
In-Reply-To: <002e01c48eef$e3e2dc40$6601a8c0@northbrook>

On Mon, Aug 30, 2004 at 06:17:24PM -0600, Robert Hancock wrote:
> Quite likely, in that case the drive has exhausted its spare pool, and 
> there are a bunch of bad sectors that have already been reallocated. Some 
> drives will reallocate sectors if they are still readable but the sector 
> appears to be marginal.

I agree that this is the theory. In practise however, I've never
seen it work correctly. We've seen several disks with say 1-5 bad
blocks and nothing else, and "dd if=/dev/zero of=/dev/<disk>" doesn't
seem to cure them.

I know how to check SMART, and I can see that some of these disks
have NEVER reallocated a block. Stuff like that. 

	Roger. 


> ----- Original Message ----- 
> From: "Rogier Wolff" <R.E.Wolff@harddisk-recovery.nl>
> Newsgroups: fa.linux.kernel
> To: "Theodore Ts'o" <tytso@mit.edu>; <linux-kernel@vger.kernel.org>; 
> <linux-ide@vger.kernel.org>
> Sent: Monday, August 30, 2004 4:19 PM
> Subject: Re: Driver retries disk errors.
> 
> 
> >On Mon, Aug 30, 2004 at 01:46:32PM -0400, Theodore Ts'o wrote:
> >>> a filesystem: if we recover one block this way, the next block will be
> >>> errorred and the filesystem "crashes" anyway. In fact this behaviour
> >>> may masquerade the first warnings that something is going wrong....
> >>
> >>If the block gets successfully read after 2 or 3 tries, it might be a
> >>good idea for the kernel to automatically do a forced rewrite of the
> >>block, which should cause the disk to do its own disk block
> >>sparing/reassignment.
> >
> >Hi Ted,
> >
> >I agree that this is the theory. In practise however, I've never
> >seen it work correctly. We've seen several disks with say 1-5 bad
> >blocks and nothing else, and "dd if=/dev/zero of=/dev/<disk>" doesn't
> >seem to cure them.
> >
> >Roger.
> >
> >-- 
> >+-- Rogier Wolff -- www.harddisk-recovery.nl -- 0800 220 20 20 --
> >| Files foetsie, bestanden kwijt, alle data weg?!
> >| Blijf kalm en neem contact op met Harddisk-recovery.nl!
> >-
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> >the body of a message to majordomo@vger.kernel.org
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> >Please read the FAQ at  http://www.tux.org/lkml/ 
> 
> -
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-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
**** "Linux is like a wigwam -  no windows, no gates, apache inside!" ****

  reply	other threads:[~2004-09-01 23:13 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.d48te6f.1ol6tbb@ifi.uio.no>
     [not found] ` <fa.eti1vu1.2nqlj5@ifi.uio.no>
2004-08-31  0:17   ` Driver retries disk errors Robert Hancock
2004-09-01 23:04     ` Rogier Wolff [this message]
2004-08-30 16:39 Rogier Wolff
2004-08-30 17:46 ` Theodore Ts'o
2004-08-30 18:26   ` James Courtier-Dutton
2004-08-30 22:25     ` Rogier Wolff
2004-08-31 11:38     ` Alan Cox
2004-09-02 16:23       ` Eric Mudama
2004-08-31 15:16     ` Bill Davidsen
2004-08-30 22:17   ` Rogier Wolff
2004-08-31 11:45 ` Alan Cox
2004-08-31 13:45   ` Andre Hedrick
2004-08-31 13:54   ` Rogier Wolff
2004-08-31 14:12     ` Alan Cox
2004-08-31 15:56       ` Erik Mouw
2004-08-31 15:13         ` Alan Cox
2004-08-31 17:00           ` Erik Mouw
2004-08-31 16:12             ` Alan Cox
2004-09-01 15:18               ` Bill Davidsen
2004-09-01 14:46                 ` Alan Cox
2004-09-01 18:54                   ` Bill Davidsen
2004-09-01 15:28               ` Romano Giannetti
2004-09-01 14:44                 ` Alan Cox
2004-09-01 23:14                   ` Rogier Wolff
2004-09-02  9:29                     ` Alan Cox
2004-09-02 10:54                       ` Rogier Wolff
2004-09-02 14:30                       ` John Stoffel
2004-09-02 14:59                         ` Alan Cox
2004-09-02 16:07                           ` John Stoffel
2004-09-02 16:26                   ` Eric Mudama
2004-08-31 22:55           ` Christer Weinigel

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