In addition to my MBP late 2011 17" 750GB HD (530GB free), I have a Mac Mini Server late 2011 (hardwired) with dual 500GB 7200RPM hard drives ("Server HD" with 340GB free & "Macintosh HD2" with 499GB free), which shares files with my MBP. Both machines are running OS X Lion 10.7.5, which came pre-installed (no disk). I've never used Time Machine on either machine & I don't have an external drive. How would you setup 2 Macs like this to be backed up on an ongoing basis? Thanks!