[BlueOnyx:17632] Raid1 issue

[Tom]

It appears one of my new hard drives is defective and failing. I replaced 
the drive with a new one. An hour or so has gone by and I received an email 
that RAID has failed. So I ran cat /proc/mdstat and received the following:

[root at ns ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[1]
      819136 blocks super 1.0 [2/1] [_U]

md126 : active (auto-read-only) raid1 sdb2[0]
      243625852 blocks super 1.1 [2/1] [U_]
      bitmap: 2/2 pages [8KB], 65536KB chunk

md127 : active (auto-read-only) raid1 sdb1[0]
      511988 blocks super 1.0 [2/1] [U_]

md1 : active raid1 sda2[1]
      243188736 blocks super 1.1 [2/1] [_U]
      bitmap: 2/2 pages [8KB], 65536KB chunk

Do I need to recreate the RAID1 or wait for it to rebuild on its own?

Thanks in advance.