Seems like mac pro back-up configuration threads are popular these days. I thought I would post another... I have three 750GB drives and I am mildly paranoid about backing-up. Currently I have two drives mounted internally and I clone the boot volume to the back-up drive every night at 2am. The back-up is set-up such that old files are not deleted from the back-up drive. This provides some measure multiple back-ups, in that if I have deleted a file I want I *might* be able to find it on the back-up drive. The third drive is used for more occasional back-ups and is stored off-site. The problem is that I don't want to go through the bother of back-up/shutdown/pull-drive/reboot whenever I need to do this. Unfortunately, the internal drives are not hot-swappable. Total bummer. I started to wonder if it made any sense to pin the internal SATA connections for drive 3&4 to a PCI slot on the back of the machine. This would allow me to plug/unplug the drives without re-booting. Is this a bad idea? Can they be unplugged safely after they are unmounted? Alternately, I could buy an enclosure, but there is not SATA on the back of the machine so I would need to use USB2/FW400/FW800. Is there a better way? Should I use these 3 drives in a different configuration?