[CentOS] Installing/configuring a second HD

My old server was Centos 4.8 and it is on a HD that is NOT connected. The new Centos 5.5 is the active HD. Everything appears to be working, so my intent is to jumper the old HD as a slave, wipe it clean and have it as a backup drive. Since my Linux skills are minimum, I thought it best to heck with the experts to find the best (safest) way to accomplish my goal.

I assume that the old drive will auto-mount, however I am not sure if it will be identified as a separate due to the Volume system (I am not near my server at the moment and I cannot remember the exact name that is used for the HD configuration). I would notwant to format the drive and find out everything was formatted.

Todd