I need large, fast storage for video files AND I want redundancy. Here's what I THINK I want: to make an 8 TB RAID 0 out of two 4 TB drives, and a concatenation of two 4 TB drives as a backup volume. What do I really want? Suppose price isn't a consideration. Also, suppose price IS a consideration. What do I need? I don't have a machine with thunderbolt yet but I'll probably buy this newfangled Mac Pro, so that may suggest certain future options. Currently on a Mac Pro 3,1 with 4 filled drive bays and a lot of external firewire crap.