I think you guys should use SAN or filesystem snapshots that can be done almost instantly. ZFS can do it, btrfs can do it, LVM can do it, most SANs can do it. It would save you extra space instead of making a copy of the data. Would also mean I can hit a snap and move on with my life instead of getting so bored waiting for a snap that I A.D.D. off onto another task and not make it back to what I was doing for days.