RAID

Rebuilding a failed array.

1) the old state

/dev/md0 is /dev/hda1 and /dev/hdc1

has /dev/hda failed

2) replace /dev/hda

3) partition /dev/hda to create RAID containers like hdc. They must be the same size as the partitions on the other disk, and of type fd (Linux raid autodetect)

4) mdadm --add /dev/md0 /dev/hda1

5) To monitor progress: cat /proc/mdstat

6) Optional: regrub the disk if this is /boot