From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Kortschak Subject: query re: resync not persisting over reboot in rescue mode Date: Mon, 24 Oct 2016 10:20:40 +1030 Message-ID: <1477266640.7137.13.camel@adelaide.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids First, I'll start with an apology - I have little (~nothing) in the way of hard data to back up this question, but it is now just a matter of personal interest as the problem appears to be fixed. Background: Last week I tried to upgrade a kernel (ubuntu distro 16.04) but that failed due to out of space (the system was originally built when kernels were much smaller and I have now got to the point where it is not possible to have two kernels on the /boot partitian). On reboot the boot failed with a great deal of disk noise which persisted. Booting into recovery worked, and the noise was now knowable to be coming from a RAID resync of /dev/md0 (RAID10) after I dropped into a root shell. I allowed this to complete and then went back to resume the normal boot. This failed as before. Repeating the process above, I found that the RAID was again unsynced an doing a resync. This has now resolved - I again allowed the resync to complete and then did a /sbin/reboot from the CLI rather than going back to the recovery menu and continuing the boot from the menu. Question: What is a/are likely cause(s) for a resync to not persist over a reboot? Thanks and apologies for the dearth of information (if more will be helpful I can add in a follow-up, but since the RAID is now working I am not sure what will be helpful). Dan Current detail (now all working): $ sudo mdadm --detail /dev/md0 /dev/md0:         Version : 0.90   Creation Time : Tue Sep 29 17:41:02 2009      Raid Level : raid10      Array Size : 974558208 (929.41 GiB 997.95 GB)   Used Dev Size : 974558208 (929.41 GiB 997.95 GB)    Raid Devices : 4   Total Devices : 4 Preferred Minor : 0     Persistence : Superblock is persistent     Update Time : Mon Oct 24 09:47:52 2016           State : active   Active Devices : 4 Working Devices : 4  Failed Devices : 0   Spare Devices : 0          Layout : far=4      Chunk Size : 256K            UUID : xxxxxxxx:xxxxxxxx:xxxxxxxx:xxxxxxxx          Events : 0.48263     Number   Major   Minor   RaidDevice State        0       8       18        0      active sync   /dev/sdb2        1       8        2        1      active sync   /dev/sda2        2       8       34        2      active sync   /dev/sdc2        3       8       50        3      active sync   /dev/sdd2 $ cat /proc/mdstat  Personalities : [raid10] [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4]  md1 : active raid1 sdd1[3] sdc1[2] sdb1[1] sda1[0]       152512 blocks [4/4] [UUUU]        md0 : active raid10 sdd2[3] sdc2[2] sda2[1] sdb2[0]       974558208 blocks 256K chunks 4 far-copies [4/4] [UUUU]        unused devices: