[CentOS] raid 1

>>> It might be easier to swap the old sdb into the sda position so you'll 
>>> boot from it, but you should also be able to boot the install cd with
>> 
>> If swapped and booted, and got a kernel panic error.
> 
> What does it complain about?
<snip>
mounting root filesystem cfs: can't find ext3 filesystem on dev md2
mount: error 22 mounting ext
mount: error 22 mounting none switching to new root 
switchroot: mount failed: 22 
unmount /initrd/dev failed: 2
Kernel panic - not syncing: attempted to kill init!