Comment 147 for bug 120375

My server was in 8.04 LTS, having a raid 1 setup with 2 mirrored harddisk.
I have tested, if I unplug one of the disk, the raid 1 was working fine.

Sadly, after upgraded my system to 10.04.1 LTS, if I unplug one of the disk and boot, the raid 1 become inactive.

#mdadm --detail /dev/md0
mdadm: md device /dev/md0 does not appear to be active.

# cat /proc/mdstat
md0 : inactive sdb1[0](S)

I have removed some of the messages to save space here. In the above case, I have unplug the sdc, the raid 1 is not working anymore. It treated the sdb as spare disk.

If I plug back the sdc, the raid 1 will be back to normal. It doesn't make any sense.

Honestly, I am not a real expert in system admin. I implemented the software raid is simply to protect my data in case of a harddisk failure. Now I need to pray for both disk working in order for this raid 1 keeping a live..... really frustrating.

MAY I KNOW, what I need to do to fix this problem?

Thank you very much!