[GRLUG] RAID recovery

[L. V. Lammert]

Has a power failure at a site today and the UPS batteries ran out. Had
some strange problems on restart, and I realize two disks are missing
from the RAID6 volume:

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       8       34        1      active sync   /dev/sdc2
       2       0        0        2      removed
       3       0        0        3      removed


The weird part is that all four disks show active (sda2, sdb2, sdc2,
sdd2) in fdisk, but when I try to add one of the missing disks to the
array, it shows all three busy:

mdadm --assemble --run --force --update=resync /dev/md0 /dev/sda2
/dev/sdc2 /dev/sdb2

          State : active, degraded
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

Any pointers on the correct ray to resync the array?

	Thanks!

	Lee