Hello all
I'm trying to save data from a QNAP device which utilizes linux software RAID.
The RAID format used is RAID 10. The disks were handed to me after it was
decided a professional data recovery would cost too much for the data involved.
>From what I can tell the following happened (I'm not sure as I wasn't there):
* The original RAID 10 array had 4 disks
* Array was expanded to 6 disks
* Filesystem has been resized
* Array was shrunk or rebuilt with 4 disks (remaining in RAID 10)
* The filesystem became unmountable.
The system has been booted with system rescue cd, which automatically starts
RAID arrays. This is the output from /proc/mdstat at this point:
---- cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md127 : inactive sdd3[5](S) sda3[4](S)
3903891200 blocks
md13 : active raid1 sdf4[0] sdd4[5] sda4[4] sdb4[3] sde4[2] sdc4[1]
458880 blocks [8/6] [UUUUUU__]
bitmap: 48/57 pages [192KB], 4KB chunk
md8 : active raid1 sdf2[0] sdd2[5](S) sda2[4](S) sde2[3](S) sdb2[2](S) sdc2[1]
530048 blocks [2/2] [UU]
md9 : active raid1 sdf1[0] sdd1[5] sda1[4] sde1[3] sdb1[2] sdc1[1]
530048 blocks [8/6] [UUUUUU__]
bitmap: 65/65 pages [260KB], 4KB chunk
md0 : active raid10 sdf3[0] sde3[3] sdb3[2] sdc3[1]
3903891200 blocks 64K chunks 2 near-copies [4/4] [UUUU]
unused devices: <none>
When I try to mount /dev/md0, it fails with this kernel message:
[ 505.657356] EXT4-fs (md0): bad geometry: block count 1463959104 exceeds size of device (975972800 blocks)
If I skim /dev/md0 with "more", I do see random text data (the array was mainly
used for logging, so I see a lot of plaintext), so I suspect there is intact
data present.
What would be the best course of action here? Recreate the RAID array with
--assume-clean? I don't have room to create a backup of all the component
devices, risks known.
I recorded mdadm -E for every component:
---- mdadm -E /dev/sda3
/dev/sda3:
Magic : a92b4efc
Version : 0.90.00
UUID : ee50da6d:d084f704:2f17ef00:379899ff
Creation Time : Fri May 2 07:16:58 2014
Raid Level : raid10
Used Dev Size : 1951945472 (1861.52 GiB 1998.79 GB)
Array Size : 5855836416 (5584.56 GiB 5996.38 GB)
Raid Devices : 6
Total Devices : 4
Preferred Minor : 0
Update Time : Sun May 4 10:22:16 2014
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 2
Spare Devices : 0
Checksum : 411699c7 - correct
Events : 15
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 4 8 67 4 active sync /dev/sde3
0 0 8 3 0 active sync /dev/sda3
1 1 0 0 1 faulty removed
2 2 8 35 2 active sync /dev/sdc3
3 3 0 0 3 faulty removed
4 4 8 67 4 active sync /dev/sde3
5 5 8 83 5 active sync /dev/sdf3
---- mdadm -E /dev/sdb3
/dev/sdb3:
Magic : a92b4efc
Version : 0.90.00
UUID : 05b41ebc:0bd1a5ce:4778a22f:da014845
Creation Time : Sun May 4 11:04:37 2014
Raid Level : raid10
Used Dev Size : 1951945600 (1861.52 GiB 1998.79 GB)
Array Size : 3903891200 (3723.04 GiB 3997.58 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Mon May 5 14:30:00 2014
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : f75212f1 - correct
Events : 6
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 2 8 3 2 active sync /dev/sda3
0 0 8 19 0 active sync /dev/sdb3
1 1 8 51 1 active sync /dev/sdd3
2 2 8 3 2 active sync /dev/sda3
3 3 8 35 3 active sync /dev/sdc3
---- mdadm -E /dev/sdc3
/dev/sdc3:
Magic : a92b4efc
Version : 0.90.00
UUID : 05b41ebc:0bd1a5ce:4778a22f:da014845
Creation Time : Sun May 4 11:04:37 2014
Raid Level : raid10
Used Dev Size : 1951945600 (1861.52 GiB 1998.79 GB)
Array Size : 3903891200 (3723.04 GiB 3997.58 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Mon May 5 14:30:00 2014
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : f752131f - correct
Events : 6
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 1 8 51 1 active sync /dev/sdd3
0 0 8 19 0 active sync /dev/sdb3
1 1 8 51 1 active sync /dev/sdd3
2 2 8 3 2 active sync /dev/sda3
3 3 8 35 3 active sync /dev/sdc3
---- mdadm -E /dev/sdd3
/dev/sdd3:
Magic : a92b4efc
Version : 0.90.00
UUID : ee50da6d:d084f704:2f17ef00:379899ff
Creation Time : Fri May 2 07:16:58 2014
Raid Level : raid10
Used Dev Size : 1951945472 (1861.52 GiB 1998.79 GB)
Array Size : 5855836416 (5584.56 GiB 5996.38 GB)
Raid Devices : 6
Total Devices : 4
Preferred Minor : 0
Update Time : Sun May 4 10:22:16 2014
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 2
Spare Devices : 0
Checksum : 411699d9 - correct
Events : 15
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 5 8 83 5 active sync /dev/sdf3
0 0 8 3 0 active sync /dev/sda3
1 1 0 0 1 faulty removed
2 2 8 35 2 active sync /dev/sdc3
3 3 0 0 3 faulty removed
4 4 8 67 4 active sync /dev/sde3
5 5 8 83 5 active sync /dev/sdf3
---- mdadm -E /dev/sde3
/dev/sde3:
Magic : a92b4efc
Version : 0.90.00
UUID : 05b41ebc:0bd1a5ce:4778a22f:da014845
Creation Time : Sun May 4 11:04:37 2014
Raid Level : raid10
Used Dev Size : 1951945600 (1861.52 GiB 1998.79 GB)
Array Size : 3903891200 (3723.04 GiB 3997.58 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Mon May 5 14:30:00 2014
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : f7521313 - correct
Events : 6
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 3 8 35 3 active sync /dev/sdc3
0 0 8 19 0 active sync /dev/sdb3
1 1 8 51 1 active sync /dev/sdd3
2 2 8 3 2 active sync /dev/sda3
3 3 8 35 3 active sync /dev/sdc3
---- mdadm -E /dev/sdf3
/dev/sdf3:
Magic : a92b4efc
Version : 0.90.00
UUID : 05b41ebc:0bd1a5ce:4778a22f:da014845
Creation Time : Sun May 4 11:04:37 2014
Raid Level : raid10
Used Dev Size : 1951945600 (1861.52 GiB 1998.79 GB)
Array Size : 3903891200 (3723.04 GiB 3997.58 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Update Time : Mon May 5 14:30:00 2014
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : f75212fd - correct
Events : 6
Layout : near=2
Chunk Size : 64K
Number Major Minor RaidDevice State
this 0 8 19 0 active sync /dev/sdb3
0 0 8 19 0 active sync /dev/sdb3
1 1 8 51 1 active sync /dev/sdd3
2 2 8 3 2 active sync /dev/sda3
3 3 8 35 3 active sync /dev/sdc3
Thanks,
Best regards,
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