Greetings gents. I may have missed it, but i haven't seen this suggested yet: RAID+LVM. If you already have a 3TB drive, buy another (or two more) and build a RAID1 or 5 array on them. Then build your LVM on top of /dev/md0 (or whatever device your raid is).
Another approach is ZFS with RAID-Z or similar. I don't know how/if ZFS splits data among the drives, but i assume it's wise enough to do so in a way similar to a RAID+LVM combo. If going RAID, make sure the rpm and cache are the same for performance's sake, and you can mix and match drives from different vendors (perhaps you should, to add to the redundancy). I don't know about btrfs, seems like it's still in a testing-phase so i'm not touching it yet. Just my 2¢ Cheers, Nuno
