Hello,

i have a little problem. Our server has an broken RAID.

# cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sda1[2](F) sdb1[1] 2096064 blocks [2/1] [_U]

md2 : active raid1 sda3[2](F) sdb3[1] 1462516672 blocks [2/1] [_U]

md1 : active raid1 sda2[0] sdb2[1] 524224 blocks [2/2] [UU]

unused devices: <none>

I have remove the partition:

# mdadm --remove /dev/md0 /dev/sda1 mdadm: hot removed /dev/sda1 from /dev/md0

# mdadm --remove /dev/md2 /dev/sda3 mdadm: hot removed /dev/sda3 from /dev/md2

Now i want to add the old partition (to sync the raid), unfortunately, comes an error message: # mdadm --add /dev/md0 /dev/sda1 mdadm: failed to write superblock to /dev/sda1

What is wrong here? Here some more details:

# mdadm --detail /dev/md0 /dev/md0: Version : 0.90 Creation Time : Fri Sep 2 12:38:17 2011 Raid Level : raid1 Array Size : 2096064 (2047.28 MiB 2146.37 MB) Used Dev Size : 2096064 (2047.28 MiB 2146.37 MB) Raid Devices : 2 Total Devices : 1 Preferred Minor : 0 Persistence : Superblock is persistent

Update Time : Thu Jun 7 08:57:12 2012 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0

UUID : 9beaf2eb:4b5c7416:776c2c25:004bd7b2 Events : 0.147

Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1

Thanks Sebastian