[CentOS] Recover RAID

[John R Pierce]

Jeff Sadino wrote:
> Do you think I can copy the unknown partition from the second drive 
> onto the first drive and have everything work again?

if there's a md mirror, god knows what will happen when you boot it up 
with both drives present, it oculd decide to mirror the unformatted 
partition to the original, I've seen worse happen when the juju is 
messed with.

I think I'd totally wipe the drive you messed with, like zero it.   Then 
boot up the system in single user with just the one drive you didn't 
hose, and BACK UP EVERYTHING ON IT TO EXTERNAL SAFE MEDIA.  use dump or 
something to do the backup that does a proper inode level backup of each 
volume.   then add the wiped/blank drive, and remirror it with the mdadm 
commands to repair the raid, then reboot to normal mode and see if its 
all safe.