I'm currently running a Debian 6.0 server with EXT3, but I'd like to move over to Arch. It's being used as a file server right now with a 1TB drive in it (of which 650GB in it is used). What I'd like to do at a later point (when I'm not completely broke) is buy another drive and add it to the same system (for backing up my main rig). What would be the easiest way of accomplishing this? I've looked into RAID, but it'd be useless because I'd have to reinitialize the array every time I added a new drive. Note: I'm not fussed about redundancy, it's only going to be hosting mirrored backups which I can easily remake in the case of data loss.
Basically: System with clean 1TB drive in, what should I do now to prepare for a new striped drive at a later date without having to reinitialize any arrays?