From: Neil Brown <neilb@suse.de>
To: Peter Rabbitson <rabbit@rabbit.us>
Cc: linux-raid@vger.kernel.org
Subject: Re: mismatch_cnt questions - how about raid10?
Date: Mon, 12 Mar 2007 16:35:35 +1100 [thread overview]
Message-ID: <17908.59047.688420.79050@notabene.brown> (raw)
In-Reply-To: message from Peter Rabbitson on Tuesday March 6
On Tuesday March 6, rabbit@rabbit.us wrote:
> >
>
> I see. So basically for those of us who want to run swap on raid 1 or
> 10, and at the same time want to rely on mismatch_cnt for early problem
> detection, the only option is to create a separate md device just for
> the swap. Is this about right?
Though it is less likely, a regular filesystem could still (I think)
genuinely write different data to difference devices in a raid1/10.
So relying on mismatch_cnt for early problem detection probably isn't
really workable.
And I think that if a drive is returning bad data without signalling
an error, then you are very much into the 'late' side of problem
detection.
I see the 'check' and 'repair' functions mostly as valuable for the
fact that they read every block and will trigger sleeping bad blocks
early. If they every find a discrepancy, then it is either perfectly
normal, or something seriously wrong that could have been wrong for a
while....
NeilBrown
next prev parent reply other threads:[~2007-03-12 5:35 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 [this message]
2007-03-12 14:26 ` Peter Rabbitson
2007-03-04 21:21 ` mismatch_cnt questions Eyal Lebedinsky
2007-03-04 22:30 ` 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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