From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bas van Schaik Subject: Doing 'echo repair > /sys/devices/virtual/block/md?/md/sync_action' does not result in mismatch_cnt of 0 on RAID-6? Date: Tue, 15 Mar 2011 11:30:59 +0000 Message-ID: <4D7F4DF3.7010804@tuxes.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids All, I'm seeing a non-zero mismatch_cnt (in fact, it's 1704) on my RAID-6 array consisting of 8 devices on kernel 2.6.38. After replacing some hardware, I decided to trigger a MD repair by issuing: echo repair > /sys/devices/virtual/block/md5/md/sync_action Directly after issuing this command, the mismatch_cnt is reset to 0 and MD starts checking the array. However, the mismatch_cnt increases during this check - resulting in exactly the same count as seen before. Shouldn't 'repair' yield a zero mismatch_cnt? I think I have seen 'repair' work on other RAID-6 arrays? Furthermore, theoretically it should be possible to indicate which device in the RAID-6 array contains the inconsistent data, or am I mistaking? If so, that would certainly be a nice feature to see implemented, as it would help diagnosing problems. Please let me know your thoughts, as I'm quite keen to get my mismatch_cnt back to 0 in order to see whether the new hardware works properly! Thanks, Bas