Hello,
it's recovery time again. Problem at hand: raid5 consisting of four
partitions, each on a drive. Two disks have failed. Assembly fails
because the slot numbers of the array components seem to be corrupt.
/dev/md0 consisting of /dev/sd[abcd]1, of which b,c failed and of
which c seems really bad in SMART, b looks reasonably OK judging from
SMART.
Checksum of the failed component superblocks was bad.
Using mdadm.conf we have already tried updating the superblocks. This
partly succeeded in the sense that checksums came up ok, the slot
numbers did not.
mdadm refuses to assemble, even with --force.
Could you guys peek over the array configuration (mdadm --examine) and
see if there is a non-destructive way to try and mount the array. If
not, what is the least intrusive way to do a non-syncing (re)create?
Data recovery is our prime concern here.
Below the uname -a, --examine output of all four drives, mdadm.conf of
what we think the array should look like and finally, the mdadm
--assemble command and output.
Note the slot numbers on /dev/sd[bc].
Thanks for any help,
with kind regards,
Leon Woestenberg
Linux localhost 2.6.16.14-axon1 #1 SMP PREEMPT Mon May 8 17:01:33 CEST
2006 i486 pentium4 i386 GNU/Linux
[root@localhost ~]# mdadm --examine /dev/sda1
/dev/sda1:
Magic : a92b4efc
Version : 00.90.00
UUID : 51a95144:00af4c77:c1cd173b:94cb1446
Creation Time : Mon Sep 5 13:16:42 2005
Raid Level : raid5
Device Size : 390620352 (372.52 GiB 400.00 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Tue Apr 17 07:03:46 2007
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : f98ed71b - correct
Events : 0.115909229
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 0 8 1 0 active sync /dev/sda1
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
2 2 8 33 2 active sync /dev/sdc1
3 3 8 49 3 active sync /dev/sdd1
[root@localhost ~]# mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a92b4efc
Version : 00.90.00
UUID : 51a95144:00af4c77:c1cd173b:94cb1446
Creation Time : Mon Sep 5 13:16:42 2005
Raid Level : raid5
Device Size : 390620352 (372.52 GiB 400.00 GB)
Raid Devices : 4
Total Devices : 5
Preferred Minor : 0
Update Time : Tue Apr 17 07:03:46 2007
State : clean
Active Devices : 5
Working Devices : 4
Failed Devices : 1
Spare Devices : 0
Checksum : e6d35288 - correct
Events : 0.115909230
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this -11221199 -1288577935 -1551230943 2035285809 faulty
active removed
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
2 2 8 33 2 active sync /dev/sdc1
3 3 8 49 3 active sync /dev/sdd1
[root@localhost ~]# mdadm --examine /dev/sdc1
/dev/sdc1:
Magic : a92b4efc
Version : 00.90.00
UUID : 51a95144:00af4c77:c1cd173b:94cb1446
Creation Time : Mon Sep 5 13:16:42 2005
Raid Level : raid5
Device Size : 390620352 (372.52 GiB 400.00 GB)
Raid Devices : 4
Total Devices : 9
Preferred Minor : 0
Update Time : Tue Apr 17 07:03:46 2007
State : clean
Active Devices : 8
Working Devices : 8
Failed Devices : 1
Spare Devices : 0
Checksum : 33e911c - correct
Events : 0.115909230
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 1038288281 293191225 29538921 -2128142983 faulty
active write-mostly
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
2 2 8 33 2 active sync /dev/sdc1
3 3 8 49 3 active sync /dev/sdd1
[root@localhost ~]# mdadm --examine /dev/sdd1
/dev/sdd1:
Magic : a92b4efc
Version : 00.90.00
UUID : 51a95144:00af4c77:c1cd173b:94cb1446
Creation Time : Mon Sep 5 13:16:42 2005
Raid Level : raid5
Device Size : 390620352 (372.52 GiB 400.00 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Tue Apr 17 07:03:46 2007
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : 7779c2 - correct
Events : 0.115909230
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 3 8 49 3 active sync /dev/sdd1
0 0 8 1 0 active sync /dev/sda1
1 1 8 17 1 active sync /dev/sdb1
2 2 8 33 2 active sync /dev/sdc1
3 3 8 49 3 active sync /dev/sdd1
[root@localhost ~]#
[root@localhost ~]# cat /tmp/mdadm.conf
DEVICE /dev/sda1 /dev/sdb1/ /dev/sdc1 /dev/sdd1
ARRAY /dev/md0 devices=/dev/sda1,/dev/sdb1,/dev/sdc1,/dev/sdd1
[root@localhost ~]# mdadm -v --assemble --scan --config=/tmp/mdadm.conf --force
mdadm: looking for devices for /dev/md0
mdadm: /dev/sda1 is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 2035285809.
mdadm: /dev/sdc1 is identified as a member of /dev/md0, slot -2128142983.
mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot 3.
mdadm: no uptodate device for slot 1 of /dev/md0
mdadm: no uptodate device for slot 2 of /dev/md0
mdadm: added /dev/sdd1 to /dev/md0 as 3
mdadm: added /dev/sda1 to /dev/md0 as 0
mdadm: /dev/md0 assembled from 2 drives - not enough to start the array.
--
Leon
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