Hello.
I've had a disk "failure" in a raid5 containing 4 drives and 1 spare.
The raid5 still reported to be clean but smart data was indicating one
drive failing. So I did these steps:
1. I shut down the system and replaced the failing drive with a new one.
2. Upon booting the system, another drive of this array was missing. I
thought it would be the spare device and tried to start the array with
the remaining 3 devices (out of the 4 non-spare), but it didn't work.
All devices were set up as spare in the array (so I also used --force
eventually, but still no luck.). So I came to the conclusion that the
missing device was not the spare device.
3. I shut down the system again and re-checked all the cables and also
re-installed the failing device and removed the new one. So, the raid
array should be (physically and the actual data on the array) in the
exact same state as before I had removed the disk.
But the raid5 array cannot be started anymore. mdadm reports that the
superblocks of the devices do not match.
Can anyone help me how to recover this raid array? I'm pretty desperate
at this point.
Here is the data of $ mdadm --examine ... of all member devices:
/dev/sda5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 610fb4f8:02dab3e7:e2fbd8a5:4828a4b0
Name : garm:1 (local to host garm)
Creation Time : Fri Jul 1 20:02:44 2011
Raid Level : -unknown-
Raid Devices : 0
Avail Dev Size : 3907023024 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : active
Device UUID : b80889b3:d910f7cf:940fe571:45fdbd79
Update Time : Thu Apr 12 17:47:39 2012
Checksum : e5c307f8 - correct
Events : 2
Device Role : spare
Array State : ('A' == active, '.' == missing)
/dev/sdb5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 610fb4f8:02dab3e7:e2fbd8a5:4828a4b0
Name : garm:1 (local to host garm)
Creation Time : Fri Jul 1 20:02:44 2011
Raid Level : -unknown-
Raid Devices : 0
Avail Dev Size : 3907023024 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : active
Device UUID : 5c645db4:15f5123c:54736b86:201f0767
Update Time : Thu Apr 12 17:47:39 2012
Checksum : 5482cd74 - correct
Events : 2
Device Role : spare
Array State : ('A' == active, '.' == missing)
/dev/sdg5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 610fb4f8:02dab3e7:e2fbd8a5:4828a4b0
Name : garm:1 (local to host garm)
Creation Time : Fri Jul 1 20:02:44 2011
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 3907023024 (1863.01 GiB 2000.40 GB)
Array Size : 11721068256 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907022752 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 0ec23618:69bcb467:20fe2b20:5dedf2d6
Internal Bitmap : 2 sectors from superblock
Update Time : Thu Apr 12 17:14:54 2012
Checksum : edbcd80f - correct
Events : 21215
Layout : left-symmetric
Chunk Size : 16K
Device Role : Active device 0
Array State : AAAA ('A' == active, '.' == missing)
/dev/sdh5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 610fb4f8:02dab3e7:e2fbd8a5:4828a4b0
Name : garm:1 (local to host garm)
Creation Time : Fri Jul 1 20:02:44 2011
Raid Level : -unknown-
Raid Devices : 0
Avail Dev Size : 3907023024 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : active
Device UUID : ff352ee9:4f8d881c:e5408fde:e6234761
Update Time : Thu Apr 12 17:47:39 2012
Checksum : bc2d09a6 - correct
Events : 2
Device Role : spare
Array State : ('A' == active, '.' == missing)
/dev/sdl5:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x1
Array UUID : 610fb4f8:02dab3e7:e2fbd8a5:4828a4b0
Name : garm:1 (local to host garm)
Creation Time : Fri Jul 1 20:02:44 2011
Raid Level : raid5
Raid Devices : 4
Avail Dev Size : 3907023024 (1863.01 GiB 2000.40 GB)
Array Size : 11721068256 (5589.04 GiB 6001.19 GB)
Used Dev Size : 3907022752 (1863.01 GiB 2000.40 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : bdf903e3:88296c06:e340658c:4378ac7b
Internal Bitmap : 2 sectors from superblock
Update Time : Sun Apr 8 20:44:46 2012
Checksum : 682f35bb - correct
Events : 21215
Layout : left-symmetric
Chunk Size : 16K
Device Role : spare
Array State : AAAA ('A' == active, '.' == missing)
Thanks in advance,
Martin Wegner
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