Wed Jul 13 14:40:22 EEST 2011

Way to get around" mdadm: /dev/md2 assembled from 1 drive - not enough to start the array."

One server with a broken Raid array was having troubles with it's software raid.
I tried to scan the raid array via a rescue cd like so:
server:~# mdadm --assemble --scan /dev/md1


just to be suprised by the message:
mdadm: /dev/md1 assembled from 2 drives - not enough to start the array.

In /proc/mdstat respectively the raid was showing inactive, e.g.:

server:~# cat /proc/mdstat
Personalities : [raid10] [raid1]
md1 : inactive sda2[0] sdc2[2] sdb2[1]
12024384 blocks


Respectively trying to activate the software Linux raid array with:
server:~# mdadm -A -s


Couldn't be completed because of the same annoying error:
/dev/md1 assembled from 2 drives - not enough to start the array.

Thanksfully finally thanks to some Russian, who posted having same issues reported to be able to active his software RAID with mdadm's --force option.

Thus enabling the problematic RAID 5 array was possible with:
server:~# mdadm -A -s --force


This solution of course is temporary and will have to further check what's wrong with the array, however at least now I can chroot to the server's / directory. ;)