From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brett Russ Subject: non-fresh data unavailable bug Date: Thu, 14 Jan 2010 10:10:57 -0500 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids 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