Now I know nobody uses this kind of raid technology anymore, but it was one of the cool things I learned from my mentor at the time, when I first started my career centuries ago. I happen to find this in my archives and thought I would write up to share.

There is another way to do this as using mdadm & sfdisk. When I find time I will share how to do that as well.

Note: If you see this, take notice to the one with [U_] this line means that the drive has fallen out of the raid.

1. To enter it back in run the lines below, based on the drive assignments in the above paritions that are good.

How to rebuild a failed drive in software if you replaced the drive:

2. recreate the paritions on the new drive by doing the following, using the same mirror drive designations from /proc/mdstat.

3. Next check the partition by running

Disk /dev/hdc: 81.9 GB, 81964302336 bytes

16 heads, 63 sectors/track, 158816 cylinders

Units = cylinders of 1008 * 512 = 516096 bytes

.

Device Boot Start End Blocks Id System

/dev/hdc1 * 1 156735 78994408+ fd Linux raid autodetect

/dev/hdc2 156736 157775 524160 fd Linux raid autodetect

/dev/hdc3 157776 158815 524160 fd Linux raid autodetect

.

Disk /dev/hda: 81.9 GB, 81964302336 bytes

16 heads, 63 sectors/track, 158816 cylinders

Units = cylinders of 1008 * 512 = 516096 bytes

.

Device Boot Start End Blocks Id System

/dev/hda1 * 1 156735 78994408+ fd Linux raid autodetect

/dev/hda2 156736 157775 524160 fd Linux raid autodetect

/dev/hda3 157776 158815 524160 fd Linux raid autodetect

———————————————————————

Filesystem Size Used Avail Use% Mounted on

/dev/md0 75G 11G 60G 16% /

none 251M 0 251M 0% /dev/shm

/dev/md1 496M 8.1M 463M 2% /tmp

4. Next you want it rebuild the partitions on the new drive so run the following, you will need to update your drive designation according to your drive assignment.

.

Note: the primary partition should match the new drive designation ‘dev/md0 /dev/hdc1’.