mdadm: No md superblock detected on /dev/md2

How to use TestDisk to recover lost partition
Post Reply
Message
Author
elvar
Posts: 1
Joined: 07 Nov 2013, 23:26

mdadm: No md superblock detected on /dev/md2

#1 Post by elvar » 07 Nov 2013, 23:36

Hi everyone,

First time poster. I have a 4 disk md raid array with ext4 on top of it. I had one drive failing and accidentally failed & removed the wrong drive. Long story short I pooched my superblocks of the /dev/md2 array. If I do mdadm --examine on each individual drive it does show md raid info. After having exhausted many attempts I re-created the array using the same parameters but still no go. I believe the data on 3 of the 4 drives is ok but I cannot figure out how to get at it because the partition table appears gone. Is there any hope at getting my data back or should I just plan for the worst? /dev/md2 had the standard linux partition on it with ext4. I have tried recovering the backed up superblocks but that doesn't work either. Below is the error I am seeing along with some output from the examine on the drives themselves. /dev/sdb3 is the bad drive.

mdadm --examine /dev/md2
mdadm: No md superblock detected on /dev/md2.

mdadm --detail /dev/md2
/dev/md2:
Version : 1.1
Creation Time : Thu Nov 7 18:01:44 2013
Raid Level : raid5
Array Size : 2911013376 (2776.16 GiB 2980.88 GB)
Used Dev Size : 970337792 (925.39 GiB 993.63 GB)
Raid Devices : 4
Total Devices : 3
Persistence : Superblock is persistent

Update Time : Thu Nov 7 18:01:56 2013
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0

Layout : left-symmetric
Chunk Size : 512K

Name : Microknoppix:2 (local to host Microknoppix)
UUID : 7a8772f3:90923437:cc969455:fc7efcd0
Events : 2

Number Major Minor RaidDevice State
0 8 3 0 active sync /dev/sda3
1 0 0 1 removed
2 8 35 2 active sync /dev/sdc3
3 8 51 3 active sync /dev/sdd3


mdadm --examine /dev/sda3
/dev/sda3:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x0
Array UUID : 7a8772f3:90923437:cc969455:fc7efcd0
Name : Microknoppix:2 (local to host Microknoppix)
Creation Time : Thu Nov 7 18:01:44 2013
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 1940676608 (925.39 GiB 993.63 GB)
Array Size : 2911013376 (2776.16 GiB 2980.88 GB)
Used Dev Size : 1940675584 (925.39 GiB 993.63 GB)
Data Offset : 262144 sectors
Super Offset : 0 sectors
State : clean
Device UUID : 36dd5244:e6c517d1:28b1fafe:d4bfbc9d

Update Time : Thu Nov 7 18:01:56 2013
Checksum : 92d875c3 - correct
Events : 2

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 0
Array State : A.AA ('A' == active, '.' == missing)


mdadm --examine /dev/sdb3
/dev/sdb3:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x0
Array UUID : cd0b3fec:1cc63322:e9f87250:c6b94370
Name : Microknoppix:2 (local to host Microknoppix)
Creation Time : Thu Nov 7 16:53:40 2013
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 1940676608 (925.39 GiB 993.63 GB)
Array Size : 2911013376 (2776.16 GiB 2980.88 GB)
Used Dev Size : 1940675584 (925.39 GiB 993.63 GB)
Data Offset : 262144 sectors
Super Offset : 0 sectors
State : clean
Device UUID : 0d6e256c:c4944592:ace1b27b:42ce00f4

Update Time : Thu Nov 7 17:50:01 2013
Checksum : ccc35696 - correct
Events : 34

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 1
Array State : AAAA ('A' == active, '.' == missing)


mdadm --examine /dev/sdc3
/dev/sdc3:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x0
Array UUID : 7a8772f3:90923437:cc969455:fc7efcd0
Name : Microknoppix:2 (local to host Microknoppix)
Creation Time : Thu Nov 7 18:01:44 2013
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 1940676608 (925.39 GiB 993.63 GB)
Array Size : 2911013376 (2776.16 GiB 2980.88 GB)
Used Dev Size : 1940675584 (925.39 GiB 993.63 GB)
Data Offset : 262144 sectors
Super Offset : 0 sectors
State : clean
Device UUID : a5aedac9:6517c59c:522654ea:92b4aa54

Update Time : Thu Nov 7 18:01:56 2013
Checksum : 8655029b - correct
Events : 2

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 2
Array State : A.AA ('A' == active, '.' == missing)

mdadm --examine /dev/sdd3
/dev/sdd3:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x0
Array UUID : 7a8772f3:90923437:cc969455:fc7efcd0
Name : Microknoppix:2 (local to host Microknoppix)
Creation Time : Thu Nov 7 18:01:44 2013
Raid Level : raid5
Raid Devices : 4

Avail Dev Size : 1940676608 (925.39 GiB 993.63 GB)
Array Size : 2911013376 (2776.16 GiB 2980.88 GB)
Used Dev Size : 1940675584 (925.39 GiB 993.63 GB)
Data Offset : 262144 sectors
Super Offset : 0 sectors
State : clean
Device UUID : c8c61a4d:d96d2714:0607bc57:57f346e0

Update Time : Thu Nov 7 18:01:56 2013
Checksum : 79fb90ab - correct
Events : 2

Layout : left-symmetric
Chunk Size : 512K

Device Role : Active device 3
Array State : A.AA ('A' == active, '.' == missing)


Any help would be GREATLY appreciated.

Kind regards,
Elvar

Sponsored links

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests