On 07/17/2017 12:19 PM, Peter Grandi wrote:
The line that worries a bit is this:
Jul 5 21:06:18 keruru mdadm[2497]: RebuildFinished event
detected on md device /dev/md0, component device mismatches
found: 1847058224 (on raid level 6)
That seems to indicate that pretty much every block was a
mismatch. Which would have happened if you put in a blank drive
and then used '--create --assume-clean' instead of '--assemble
--force'. But '--assume-clean" explicitly skips a rebuild, and I
wonder whether you omitted that yoiu have triggered a "repair"
in 'sync_action'. Also the message is reported by 'mdadm', and
it may be that 'mdadm' was running in daemon mode and triggering
a periodic "repair". I can't remember the defaults.
HOWEVER there is a very subtle detail: the order of the devices
from '--examine' is: 0: 'sdb', 1: 'sdc', 2: 'sdd', 3: 'sde' but
you recreated the set in a different order. The order of the
devices does not matter if they have MD superblocks,.but here
you are using '--create' to make new superblocks, and they order
must match exactly the original order.
root@keruru:/var/log# mdadm --create --assume-clean --level=6 --raid-devices=4 --size=1953382912 /dev/md0 /dev/sdb /dev/sde /dev/sdd /dev/sdc
Probably the best thing you can do is to rerun this with members
"missing /dev/sdc /dev/sdd /dev/sde". and then use 'blkid /dev/md0'
to check whether the data in it is recognized again. If so add
'/dev/sdb'. I did a quick test here of something close to that
and it worked...
Thanks for responding, Peter. Much appreciated.
Did I do it right? (See below)
root@keruru:~# mdadm --create --assume-clean --level=6 --raid-devices=4
--size=1953382912 /dev/md0 missing /dev/sdc /dev/sdd /dev/sde
mdadm: /dev/sdc appears to be part of a raid array:
level=raid6 devices=4 ctime=Tue Jul 11 17:33:12 2017
mdadm: /dev/sdd appears to be part of a raid array:
level=raid6 devices=4 ctime=Tue Jul 11 17:33:12 2017
mdadm: /dev/sde appears to be part of a raid array:
level=raid6 devices=4 ctime=Tue Jul 11 17:33:12 2017
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
root@keruru:~# blkid /dev/md0
root@keruru:~#
root@keruru:~# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active (auto-read-only) raid6 sde[3] sdd[2] sdc[1]
3906765824 blocks super 1.2 level 6, 512k chunk, algorithm 2
[4/3] [_UUU]
unused devices: <none>
No reading from blkid, so I am assuming 'not good'. But I've done
nothing further in case I misunderstood your suggestion.
--
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
