Basically as of right now I have all 4 drive bays in my mac pro full, the 4th drive being my time machine backup (2tb) I've recently filled it and need more space. I can either upgrade to a 3tb which is I believe the max supported? but who knows, that could be filled up a month after doing so. I'm looking to go another route such as raid that would combine multiple tb drives into one massive time machine backup drive or just use them separately as you would using a time machine backup half on an external and the rest on an internal. I'm just looking for something simple like a 2-4 bay enclosure. If anyone has any suggestions or ideas on how to go about this, I would appreciate it.