Hello everyone
I have a raid5 mdadm array which has four drives. My new motherboard has inexplicably cleared three of the super blocks, and I am now left with only one intact superblock.
fdisk -l
Code:
Disk /dev/sda: 20.4 GB, 20490559488 bytes
255 heads, 63 sectors/track, 2491 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x03930393
Device Boot Start End Blocks Id System
/dev/sda1 * 1 1982 15920383+ 83 Linux
/dev/sda2 1983 2491 4088542+ 82 Linux swap / Solaris
Disk /dev/sdb: 1000.2 GB, 1000203804160 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/sdc: 1000.2 GB, 1000203804160 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/sdd: 1000.2 GB, 1000203804160 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000
Disk /dev/sdf: 1044 MB, 1044250624 bytes
33 heads, 32 sectors/track, 1931 cylinders
Units = cylinders of 1056 * 512 = 540672 bytes
Disk identifier: 0x9348a58e
mdadm --examine /dev/sdb
Code:
mdadm: No md superblock detected on /dev/sdb
mdadm --examine /dev/sdc
Code:
mdadm: No md superblock detected on /dev/sdc
mdadm --examine /dev/sdd
Code:
mdadm: No md superblock detected on /dev/sdd
mdadm --examine /dev/sde
Code:
/dev/sde:
Magic : a92b4efc
Version : 00.90.00
UUID : f781ba39:3975fa64:c36d41f1:ea056919
Creation Time : Mon Jan 5 14:18:27 2009
Raid Level : raid5
Used Dev Size : 976762496 (931.51 GiB 1000.20 GB)
Array Size : 2930287488 (2794.54 GiB 3000.61 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Thu Mar 19 22:39:52 2009
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : 54f44664 - correct
Events : 0.92
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 3 8 32 3 active sync /dev/sdc
0 0 8 16 0 active sync /dev/sdb
1 1 8 64 1 active sync /dev/sde
2 2 8 48 2 active sync /dev/sdd
3 3 8 32 3 active sync /dev/sdc
I have now moved the raid array back to the original file server, but the superblocks are still missing. I am able to assemble the array with only the one drive, but obviously the array cannot be started. I am also unsure about the order of the drives connected to the old server and I am worried that the drives are no longer connected in the same physical order that they originally were.
I am hoping someone with more knowledge than myself can answer a few question:
1. Can this raid array be restored? I am confident that none of the actual data has been impacted, I have only lost my superblocks...
2. If I try to recreate the raid array using
mdadm --create --assume-clean and the order of the devices is not the same as the original configuration, will mdadm erase the data on the drives?
3. If I were to buy four more identical drives to the ones that comprise the raid array, dd everything to the new drives, would I be able to test recreating the array on the new drives?
4. Is there anyway to recover data from a mdadm raid array without successfully recreating the array? I am sure the data is still there, I just can't construct the array.
thanks in advance for any advice on how to proceed with this problem.
