On Thu, 17 Oct 2013 01:36:28 -0400 John Yates <jyates65@xxxxxxxxx> wrote: > On Wed, Oct 16, 2013 at 8:07 PM, NeilBrown <neilb@xxxxxxx> wrote: > > On Wed, 16 Oct 2013 09:02:52 -0400 John Yates <jyates65@xxxxxxxxx> wrote: > > > >> On Wed, Oct 16, 2013 at 1:26 AM, NeilBrown <neilb@xxxxxxx> wrote: > >> > On Mon, 14 Oct 2013 21:59:45 -0400 John Yates <jyates65@xxxxxxxxx> wrote: > >> > > >> >> Midway through a RAID5 grow operation from 5 to 6 USB connected > >> >> drives, system logs show that the kernel lost communication with some > >> >> of the drive ports which has left my array in a state that I have not > >> >> been able to reassemble. After reseating the cable connections and > >> >> rebooting, all of the drives appear to be functioning normally, so > >> >> hopefully the data is still intact. I need advice on recovery steps > >> >> for the array. > >> >> > >> >> It appears that each drive failed in quick succession with /dev/sdc1 > >> >> being the last standing and having the others marked as missing in its > >> >> superblock. The superblocks of the other drives show all drives as > >> >> available. (--examine output below) > >> >> > >> >> >mdadm --assemble /dev/md127 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1 > >> >> mdadm: too-old timestamp on backup-metadata on device-5 > >> >> mdadm: If you think it is should be safe, try 'export MDADM_GROW_ALLOW_OLD=1' > >> >> mdadm: /dev/md127 assembled from 1 drives - not enough to start the array. > >> > > >> > Did you try following the suggestion and run > >> > > >> > export MDADM_GROW_ALLOW_OLD=1 > >> > > >> > and the try the --asssemble again? > >> > > >> > NeilBrown > >> > >> Yes I did, thanks. Not much change though. It accepts the timestamp, > >> but then appears not to use it. > >> > >> mdadm --assemble /dev/md127 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 > >> /dev/sdf1 /dev/sdg1 --verbose > >> mdadm: looking for devices for /dev/md127 > >> mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 4. > >> mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 3. > >> mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 2. > >> mdadm: /dev/sde1 is identified as a member of /dev/md127, slot 0. > >> mdadm: /dev/sdf1 is identified as a member of /dev/md127, slot 1. > >> mdadm: /dev/sdg1 is identified as a member of /dev/md127, slot 5. > >> mdadm: :/dev/md127 has an active reshape - checking if critical > >> section needs to be restored > >> mdadm: accepting backup with timestamp 1381360844 for array with > >> timestamp 1381729948 > >> mdadm: backup-metadata found on device-5 but is not needed > >> mdadm: added /dev/sdf1 to /dev/md127 as 1 > >> mdadm: added /dev/sdd1 to /dev/md127 as 2 > >> mdadm: added /dev/sdc1 to /dev/md127 as 3 > >> mdadm: added /dev/sdb1 to /dev/md127 as 4 (possibly out of date) > >> mdadm: added /dev/sdg1 to /dev/md127 as 5 (possibly out of date) > >> mdadm: added /dev/sde1 to /dev/md127 as 0 > >> mdadm: /dev/md127 assembled from 4 drives - not enough to start the array. > > > > > > What about with MDADM_GROW_ALLOW_OLD=1 *and* --force ?? > > > > If that doesn't work, please add --verbose as well, and report the output. > > > > NeilBrown > > Thanks Neil. I had tried that as well (output below). I'm wondering if > there is a way to fix the metadata for /dev/sdc1 since that seems to > be the odd one where the --examine data indicates that the other disks > are all bad when I don't believe they really are (just the result of a > partial kernel or driver crash). I have read about some people zeroing > the superblock on a device so that it can be recreated, but I am not > sure exactly how that works and am hesitant to try it since a reshape > was in progress. I have also read about people having had success by > re-running the original mdadm --create while leaving the data intact, > but again I am hesitant to try that, especially because of the reshape > state. > > Or... maybe this all has more to do with the Update Time, since the > output seems to indicate 4 drives are usable. All of the drives have > the same Update Time except for /dev/sdc1 which is about 5 minutes > later than the rest. Since it is the fourth device, perhaps the > assemble is satisfied with devices 0, 1, 2, 3, but then seeing an > Update Time on devices 4 and 5 that is earlier than device 3, it > marks them as "possibly out of date" and stops trying to assemble the > array. Hard to tell, but I still would not have any idea how to > overcome that scenario. I appreciate your help! > > # export MDADM_GROW_ALLOW_OLD=1 > # mdadm --assemble /dev/md127 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 > /dev/sdf1 /dev/sdg1 --force --verbose > mdadm: looking for devices for /dev/md127 > mdadm: /dev/sdb1 is identified as a member of /dev/md127, slot 4. > mdadm: /dev/sdc1 is identified as a member of /dev/md127, slot 3. > mdadm: /dev/sdd1 is identified as a member of /dev/md127, slot 2. > mdadm: /dev/sde1 is identified as a member of /dev/md127, slot 0. > mdadm: /dev/sdf1 is identified as a member of /dev/md127, slot 1. > mdadm: /dev/sdg1 is identified as a member of /dev/md127, slot 5. > mdadm: :/dev/md127 has an active reshape - checking if critical > section needs to be restored > mdadm: accepting backup with timestamp 1381360844 for array with > timestamp 1381729948 > mdadm: backup-metadata found on device-5 but is not needed > mdadm: added /dev/sdf1 to /dev/md127 as 1 > mdadm: added /dev/sdd1 to /dev/md127 as 2 > mdadm: added /dev/sdc1 to /dev/md127 as 3 > mdadm: added /dev/sdb1 to /dev/md127 as 4 (possibly out of date) > mdadm: added /dev/sdg1 to /dev/md127 as 5 (possibly out of date) > mdadm: added /dev/sde1 to /dev/md127 as 0 > mdadm: /dev/md127 assembled from 4 drives - not enough to start the array. That shouldn't happen. With '-f' it should force the event count of either b1 or g1 (or maybe both) to match the others. What version of mdadm are you using? (mdadm -V) Maybe try the latest git clone git://git.neil.brown.name/mdadm cd mdadm make mdadm ./mdadm ..... NeilBrown
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