How to integrate HDD into raid array after replacement?

postcd · 04-12-2014, 05:07 AM

Quote:

Integration of the new drive
Once the defective drive has been removed and the new one installed, it needs to be intagrated into the RAID array. This needs to be done for each partition.
# mdadm /dev/md0 -a /dev/sdb1
# mdadm /dev/md1 -a /dev/sdb2
# mdadm /dev/md2 -a /dev/sdb3
# mdadm /dev/md3 -a /dev/sdb4
The new drive is now part of the array and will be synchronized. Depending on the size of the partitions this procedure can take some time. The status of the synchronization can be observed using cat /proc/mdstat.

I have only 2 drives, what exact commands to do after one was replaced as faulty please?

Ser Olmy · 04-12-2014, 10:17 PM

You say you have two drives, but that doesn't really say anything about how your RAID array is configured.

Both devices (entire drives) and partitions can be components in an mdadm RAID array. You may have only two drives, but you could still have more than one md device.

If one drive fails, this is what you'll need to do after the drive has been replaced:

Partition the new drive in a similar fashion to the remaining drive (or not at all, if the array components are raw devices)
Run mdadm --add <md_array> <new_device_component> to add the new device to the existing md array
Repeat step 2 for every md array
(optional) Run mdadm --detail <md_array> to verify that the rebuild process has started

The rebuild/resync process will take some time, depending on the size of the array.