RAID1 software - 1 disk DEAD
 

Ok, I need help here!

I have a remote machine that has the following setup:

2x 250Gb SATA drive build in RAID 1 software using mdadm

Problem: 1 of the 2 disks is DEAD and needs to be replaced. I don't personally have access to the computer, but a person over there has access (he can put a new drive in, but don't have a clue on how to configure).

My questions:
What is the procedure when you want to do such an operation? Simply put the disk and the RAID1 will sync again? This would be to good to be true!

We have configure the array using UUID does that need to be changed if new drive is inserted?

Do we need to repartition the drive?

Thanks

Claude

You need to format the new disk identically to the existing one.

Tou can issue this command:

fdisk -l

This will give you lots of information about how the drives are partitioned. You can also do things like fdisk -l /dev/md0 or fdisk -l /dev/sda1.

With that in mind you can go through the drives and see things like this:

mdadm --detail /dev/md0

You will see that you'll get something like this:

Number Major Minor RaidDevice State
0 0 0 - removed
1 3 1 1 active sync /dev/sda1
You must then reactivate your drive. In this case you would issue this command:

mdadm --manage /dev/md0 --add /dev/sdb1

Go and do the same for the other drives. If you issue the /cat/proc/mdstat command at anytime, you will see it telling you it is resnycronising the disks.

You can do all this with ssh, so should be able to do it remotely.