Hello all,
I had a disk fail in a raid 5 array (4 disk array, no spares), and am
having trouble recovering it. I believe my data is still safe, but I
cannot tell what is going wrong here.
When I try to rebuild the array "mdadm --assemble /dev/md0 /dev/sda2
/dev/sdb2 /dev/sdc2 /dev/sdd2" I see "failed to RUN_ARRAY /dev/md0:
Input/output error".
dmesg shows the following:
md: bind<sdb2>
md: bind<sdc2>
md: bind<sdd2>
md: bind<sda2>
md: md0: raid array is not clean -- starting background reconstruction
raid5: device sda2 operational as raid disk 0
raid5: device sdc2 operational as raid disk 2
raid5: device sdb2 operational as raid disk 1
raid5: cannot start dirty degraded array for md0
RAID5 conf printout:
--- rd:4 wd:3 fd:1
disk 0, o:1, dev:sda2
disk 1, o:1, dev:sdb2
disk 2, o:1, dev:sdc2
raid5: failed to run raid set md0
md: pers->run() failed ...
/proc mdstat shows:
md0 : inactive sda2[0] sdd2[3](S) sdc2[2] sdb2[1]
This seems wrong, as sdd2 should not be a spare - I want it to be the
fourth disk.
The output of mdadm -E for each disk is as follows:
sda2:
/dev/sda2:
Magic : a92b4efc
Version : 00.90.00
UUID : c50a81fc:ef4323e6:438a7cb1:25ae35e5
Creation Time : Thu Jun 1 21:13:58 2006
Raid Level : raid5
Device Size : 390555904 (372.46 GiB 399.93 GB)
Array Size : 1171667712 (1117.39 GiB 1199.79 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Sun Oct 22 23:39:06 2006
State : active
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Checksum : 683f2f5c - correct
Events : 0.8831997
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 0 8 2 0 active sync /dev/sda2
0 0 8 2 0 active sync /dev/sda2
1 1 8 18 1 active sync /dev/sdb2
2 2 8 34 2 active sync /dev/sdc2
3 3 0 0 3 faulty removed
4 4 8 50 4 spare /dev/sdd2
sdb2:
/dev/sdb2:
Magic : a92b4efc
Version : 00.90.00
UUID : c50a81fc:ef4323e6:438a7cb1:25ae35e5
Creation Time : Thu Jun 1 21:13:58 2006
Raid Level : raid5
Device Size : 390555904 (372.46 GiB 399.93 GB)
Array Size : 1171667712 (1117.39 GiB 1199.79 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Sun Oct 22 23:39:06 2006
State : active
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Checksum : 683f2f6e - correct
Events : 0.8831997
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 1 8 18 1 active sync /dev/sdb2
0 0 8 2 0 active sync /dev/sda2
1 1 8 18 1 active sync /dev/sdb2
2 2 8 34 2 active sync /dev/sdc2
3 3 0 0 3 faulty removed
4 4 8 50 4 spare /dev/sdd2
sdc2:
/dev/sdc2:
Magic : a92b4efc
Version : 00.90.00
UUID : c50a81fc:ef4323e6:438a7cb1:25ae35e5
Creation Time : Thu Jun 1 21:13:58 2006
Raid Level : raid5
Device Size : 390555904 (372.46 GiB 399.93 GB)
Array Size : 1171667712 (1117.39 GiB 1199.79 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Sun Oct 22 23:39:06 2006
State : active
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Checksum : 683f2f80 - correct
Events : 0.8831997
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 2 8 34 2 active sync /dev/sdc2
0 0 8 2 0 active sync /dev/sda2
1 1 8 18 1 active sync /dev/sdb2
2 2 8 34 2 active sync /dev/sdc2
3 3 0 0 3 faulty removed
4 4 8 50 4 spare /dev/sdd2
sdd2:
/dev/sdd2:
Magic : a92b4efc
Version : 00.90.00
UUID : c50a81fc:ef4323e6:438a7cb1:25ae35e5
Creation Time : Thu Jun 1 21:13:58 2006
Raid Level : raid5
Device Size : 390555904 (372.46 GiB 399.93 GB)
Array Size : 1171667712 (1117.39 GiB 1199.79 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Sun Oct 22 23:39:06 2006
State : active
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Checksum : 683f2fbf - correct
Events : 0.8831997
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 3 8 50 -1 sync /dev/sdd2
0 0 8 2 0 active sync /dev/sda2
1 1 8 18 1 active sync /dev/sdb2
2 2 8 34 2 active sync /dev/sdc2
3 3 8 50 -1 sync /dev/sdd2
4 4 8 50 4 spare /dev/sdd2
Does anyone have any idea how to get this array back into good shape?
I'm not sure why it thinks sdd2 should be a spare, or how to get it back
to being a regular disk.
I would appreciate any help you can offer. (Also, am I right in thinking
my data is still good? I should still have 3 of the 4 disks working fine,
at any rate.)
Thanks,
Eric
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