Hello RAID folks - Reference my old thread at http://marc.info/?l=linux-raid&m=143880359028232&w=2 which I'm just now getting back around to working on, the delay having been caused by my need to clone a failing disk. Recall that I was attempting to grow a 5-disk RAID 6 array to 6 disks, but writing to the backup-file was inhibited by SELinux. # mdadm --add /dev/md4 /dev/sdi1 # mdadm --grow --raid-devices=6 --backup-file=/home/gwr/2015/2015-08/grow_md4.bak /dev/md4 The second command threw a bunch of SELinux errors about access to /home/gwr/c/grow_md4.bak. The reshape operation sat for many minutes at 0% progress, according to /proc/mdstat. However, the file /home/gwr/c/grow_md4.bak *was* created with a size of 6295552 bytes/ I appeared to experience a segmentation fault or other runtime error when attempting to stop the RAID 6 array with "#mdadm --stop /dev/md4". System log from that situation has been uploaded to https://app.box.com/s/3pksam3c7n79anpnzvsrwekzqwtsvlf6 Notably, the backup file was created, but contains all zero/null characters. My most recent raid.status file (generated using command "# mdadm --examine /dev/sd[cdg]4 /dev/sd[hij]1" - and, yes, I know my partition layout is a mess) has been uploaded to https://app.box.com/s/pbienbpdanr0rq224b9ag2qu36vk76iv What I find interesting about this status file is that the reshape of the array appears to have made no progress (note the presence of " Reshape pos'n : 0 " on all six devices). I have been using the recovery advice found at https://raid.wiki.kernel.org/index.php/RAID_Recovery and https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID, especially the part about creating overlay files so as not to damage my actual disks. The overlay devices are in the variable $OVERLAYS. When I attempt to assemble the RAID 6 array using the backup file, I get this: # mdadm --assemble --verbose --force --backup-file=/home/gwr/2015/2015-08/grow_md6.bak /dev/md4 $OVERLAYS mdadm: looking for devices for /dev/md4 mdadm: /dev/mapper/sdg4 is identified as a member of /dev/md4, slot 2. mdadm: /dev/mapper/sdi1 is identified as a member of /dev/md4, slot 5. mdadm: /dev/mapper/sdc4 is identified as a member of /dev/md4, slot 1. mdadm: /dev/mapper/sdh1 is identified as a member of /dev/md4, slot 3. mdadm: /dev/mapper/sdj1 is identified as a member of /dev/md4, slot 4. mdadm: /dev/mapper/sdd4 is identified as a member of /dev/md4, slot 0. mdadm: /dev/md4 has an active reshape - checking if critical section needs to be restored mdadm: No backup metadata on /home/gwr/2015/2015-08/grow_md6.bak mdadm: Failed to find backup of critical section mdadm: Failed to restore critical section for reshape, sorry. and when I omit the backup file, I get this: # mdadm --assemble --verbose --force --invalid-backup /dev/md4 $OVERLAYS mdadm: looking for devices for /dev/md4 mdadm: /dev/mapper/sdg4 is identified as a member of /dev/md4, slot 2. mdadm: /dev/mapper/sdi1 is identified as a member of /dev/md4, slot 5. mdadm: /dev/mapper/sdc4 is identified as a member of /dev/md4, slot 1. mdadm: /dev/mapper/sdh1 is identified as a member of /dev/md4, slot 3. mdadm: /dev/mapper/sdj1 is identified as a member of /dev/md4, slot 4. mdadm: /dev/mapper/sdd4 is identified as a member of /dev/md4, slot 0. mdadm: /dev/md4 has an active reshape - checking if critical section needs to be restored mdadm: Failed to find backup of critical section mdadm: continuing without restoring backup mdadm: added /dev/mapper/sdc4 to /dev/md4 as 1 mdadm: added /dev/mapper/sdg4 to /dev/md4 as 2 mdadm: added /dev/mapper/sdh1 to /dev/md4 as 3 mdadm: added /dev/mapper/sdj1 to /dev/md4 as 4 mdadm: added /dev/mapper/sdi1 to /dev/md4 as 5 mdadm: added /dev/mapper/sdd4 to /dev/md4 as 0 mdadm: /dev/md4: Need a backup file to complete reshape of this array. mdadm: Please provided one with "--backup-file=..." I even tried --update=revert-reshape; no luck: # mdadm --assemble --verbose --invalid-backup --force --update=revert-reshape /dev/md4 $OVERLAYS mdadm: looking for devices for /dev/md4 mdadm: /dev/mapper/sdg4 is identified as a member of /dev/md4, slot 2. mdadm: /dev/mapper/sdi1 is identified as a member of /dev/md4, slot 5. mdadm: /dev/mapper/sdc4 is identified as a member of /dev/md4, slot 1. mdadm: /dev/mapper/sdh1 is identified as a member of /dev/md4, slot 3. mdadm: /dev/mapper/sdj1 is identified as a member of /dev/md4, slot 4. mdadm: /dev/mapper/sdd4 is identified as a member of /dev/md4, slot 0. mdadm: /dev/md4 has an active reshape - checking if critical section needs to be restored mdadm: Failed to find backup of critical section mdadm: continuing without restoring backup mdadm: added /dev/mapper/sdc4 to /dev/md4 as 1 mdadm: added /dev/mapper/sdg4 to /dev/md4 as 2 mdadm: added /dev/mapper/sdh1 to /dev/md4 as 3 mdadm: added /dev/mapper/sdj1 to /dev/md4 as 4 mdadm: added /dev/mapper/sdi1 to /dev/md4 as 5 mdadm: added /dev/mapper/sdd4 to /dev/md4 as 0 mdadm: /dev/md4: Need a backup file to complete reshape of this array. mdadm: Please provided one with "--backup-file=..." mdadm: (Don't specify --update=revert-reshape again, that part succeeded.) How can the array have an active reshape if the reshape pos'n is 0 on all devices? Doesn't that mean that the reshape never actually started? If so, can I just revert -- somehow -- to a 5-device RAID 6 array to recover my data? Thanks. -- George Rapp (Pataskala, OH) Home: george.rapp -- at -- gmail.com LinkedIn profile: https://www.linkedin.com/in/georgerapp Phone: +1 740 936 RAPP (740 936 7277) -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
