From: Eyal Lebedinsky <eyal@eyal.emu.id.au>
To: Neil Brown <neilb@suse.de>
Cc: Christian Pernegger <pernegger@gmail.com>, linux-raid@vger.kernel.org
Subject: Re: mismatch_cnt questions
Date: Mon, 05 Mar 2007 08:21:43 +1100 [thread overview]
Message-ID: <45EB3867.8050907@eyal.emu.id.au> (raw)
In-Reply-To: <17898.45673.573800.56474@notabene.brown>
Neil Brown wrote:
> On Sunday March 4, pernegger@gmail.com wrote:
>>I have a mismatch_cnt of 384 on a 2-way mirror.
[trim]
>>3) Is the "repair" sync action safe to use on the above kernel? Any
>>other methods / additional steps for fixing this?
>
> "repair" is safe, though it may not be effective.
> "repair" for raid1 was did not work until Jan 26th this year.
> Before then it was identical in effect to 'check'.
How is "repair" safe but not effective? When it finds a mismatch, how does
it know which part is correct and which should be fixed (which copy of
raid1, or which block in raid5)?
When a disk fails we know what to rewrite, but when we discover a mismatch
we do not have this knowledge. It may corrupt the good copy of a raid1.
--
Eyal Lebedinsky (eyal@eyal.emu.id.au) <http://samba.org/eyal/>
next prev parent reply other threads:[~2007-03-04 21:21 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-04 11:22 mismatch_cnt questions Christian Pernegger
2007-03-04 11:50 ` Neil Brown
2007-03-04 12:01 ` Christian Pernegger
2007-03-04 22:19 ` Neil Brown
2007-03-06 10:04 ` mismatch_cnt questions - how about raid10? Peter Rabbitson
2007-03-06 10:20 ` Neil Brown
2007-03-06 10:56 ` Peter Rabbitson
2007-03-06 10:59 ` Justin Piszcz
2007-03-12 5:35 ` Neil Brown
2007-03-12 14:26 ` Peter Rabbitson
2007-03-04 21:21 ` Eyal Lebedinsky [this message]
2007-03-04 22:30 ` mismatch_cnt questions Neil Brown
2007-03-05 7:45 ` Eyal Lebedinsky
2007-03-05 14:56 ` detecting/correcting _slightly_ flaky disks Michael Stumpf
2007-03-05 15:09 ` Justin Piszcz
2007-03-05 17:01 ` Michael Stumpf
2007-03-05 17:11 ` Justin Piszcz
2007-03-07 0:14 ` Bill Davidsen
2007-03-07 1:37 ` Michael Stumpf
2007-03-07 13:57 ` berk walker
2007-03-07 15:01 ` Bill Davidsen
2007-03-05 23:40 ` mismatch_cnt questions Neil Brown
2007-03-07 0:22 ` Bill Davidsen
2007-03-08 6:39 ` H. Peter Anvin
2007-03-08 13:54 ` Martin K. Petersen
2007-03-09 2:00 ` Bill Davidsen
2007-03-09 4:20 ` H. Peter Anvin
2007-03-09 5:20 ` Bill Davidsen
2007-03-08 6:34 ` H. Peter Anvin
2007-03-08 7:00 ` H. Peter Anvin
2007-03-08 8:21 ` H. Peter Anvin
2007-03-13 9:58 ` Andre Noll
2007-03-13 23:46 ` H. Peter Anvin
2007-03-06 6:27 ` Paul Davidson
2008-05-12 11:16 ` Bas van Schaik
2008-05-12 14:31 ` Justin Piszcz
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