I have a raid1 array which is somehow faulty. There is 1,5 TB of stuff, I would not want to lose it (though I have full backup).

The array cannot be mounted on startup (error message was "missing superblock"). I had to boot from DVD with linux rescue and remove the array from fstab.

Here is some info - I am a little dumbfounded.

[root@a134-224 log]# cat /proc/mdstat (...) md5 : active raid1 sdb1[0] sdd1[1] 1562505856 blocks [2/2] [UU]

## mdadm examine - I believe the following output indicates that there really *is* a superblock

[root@a134-224 log]# mdadm --examine /dev/sdb1

/dev/sdb1: Magic : a92b4efc Version : 0.90.00 UUID : 194e7fdc:2a288e87:c03d8b24:c0120803 Creation Time : Sat Apr 23 20:41:08 2011 Raid Level : raid1 Used Dev Size : 1562505856 (1490.12 GiB 1600.01 GB) Array Size : 1562505856 (1490.12 GiB 1600.01 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 5

Update Time : Tue Apr 26 11:48:35 2011 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : 657d7a24 - correct Events : 14

Number Major Minor RaidDevice State this 0 8 17 0 active sync /dev/sdb1

0 0 8 17 0 active sync /dev/sdb1 1 1 8 49 1 active sync /dev/sdd1

# examine the other partition/dev/sdd1: Magic : a92b4efc Version : 0.90.00 UUID : 194e7fdc:2a288e87:c03d8b24:c0120803 Creation Time : Sat Apr 23 20:41:08 2011 Raid Level : raid1 Used Dev Size : 1562505856 (1490.12 GiB 1600.01 GB) Array Size : 1562505856 (1490.12 GiB 1600.01 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 5

Update Time : Tue Apr 26 11:48:35 2011 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Checksum : 657d7a46 - correct Events : 14

Number Major Minor RaidDevice State this 1 8 49 1 active sync /dev/sdd1

0 0 8 17 0 active sync /dev/sdb1 1 1 8 49 1 active sync /dev/sdd1

[root@a134-224 log]# mdadm --examine --scan (...) ARRAY /dev/md5 level=raid1 num-devices=2 UUID=194e7fdc:2a288e87:c03d8b24:c0120803

[root@a134-224 log]# mdadm --stop /dev/md5 mdadm: stopped /dev/md5

[root@a134-224 log]# mdadm --assemble /dev/md5 mdadm: /dev/md5 has been started with 2 drives.

# but it cannot be mounted:

[root@a134-224 log]# mount /dev/md5 /kvbck/ mount: you must specify the filesystem type [root@a134-224 log]# mount -t ext3 /dev/md5 /kvbck/ mount: wrong fs type, bad option, bad superblock on /dev/md5, missing codepage or other error In some cases useful info is found in syslog - try dmesg | tail or so

[root@a134-224 log]# tail /var/log/messages Apr 26 17:14:09 localhost kernel: md: unbind<sdb1> Apr 26 17:14:09 localhost kernel: md: export_rdev(sdb1) Apr 26 17:14:09 localhost kernel: md: unbind<sdd1> Apr 26 17:14:09 localhost kernel: md: export_rdev(sdd1) Apr 26 17:14:17 localhost kernel: md: md5 stopped. Apr 26 17:14:17 localhost kernel: md: bind<sdd1> Apr 26 17:14:17 localhost kernel: md: bind<sdb1> Apr 26 17:14:17 localhost kernel: raid1: raid set md5 active with 2 out of 2 mirrors Apr 26 17:14:56 localhost kernel: hfs: unable to find HFS+ superblock Apr 26 17:15:05 localhost kernel: VFS: Can't find ext3 filesystem on dev md5.

# Why does the log complain about HFS+ superblock? The fs should be ext3.

- Jussi