replace failure disk and rebuild RAID with mdadm
 

One of my 4 RAID disks is failed. I want to replace it with a brand new drive which i has just format it.

using mdadm --assumble /dev/md0 /dev/sdb[1234]

It saidmy sdb3 (new drive) has no superblock.

so I try

mdadm --add /dev/md0 /dev/sdb3

It does not work either.

Does anyone know how to add the drive?