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From: Brett Russ <bruss@netezza.com>
To: linux-raid@vger.kernel.org
Subject: non-fresh data unavailable bug
Date: Thu, 14 Jan 2010 10:10:57 -0500	[thread overview]
Message-ID: <hinc60$fnh$1@ger.gmane.org> (raw)

Slightly related to my last message here Re:non-fresh behavior, we have 
seen cases where the following happens:
* healthy 2 disk raid1 (disks A & B) incurs a problem with disk B
* disk B is removed, unit is now degraded
* replacement disk C is added; recovery from A to C begins
* during recovery, disk A incurs a brief lapse in connectivity.  At this 
point C is still up yet only has a partial copy of the data.
* a subsequent assemble operation on the raid1 results in disk A being 
kicked out as non-fresh, yet C is allowed in.

This presents quite a data-unavailability problem and basically requires 
recognizing the situation and hand assembling the array with disk A 
(only) first, then adding C back in.  Unfortunately this situation is 
hard to reproduce and we don't have a dump of the 'mdadm --examine' 
output for it yet.

Any thoughts on this while we try to get a better reproduction case?

Thanks,
Brett



             reply	other threads:[~2010-01-14 15:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-14 15:10 Brett Russ [this message]
2010-01-14 19:24 ` non-fresh data unavailable bug Michael Evans
2010-01-15 15:36   ` Brett Russ
2010-01-18  3:32     ` Neil Brown

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