Take! Freaking! SNAPSHOTS!

root@banshee:/data# du -hs movies

436G movies

root@banshee:/data# time zfs snapshot data/movies@1

real 0m0.150s

root@banshee:/data# time rm -rf movies

real 12m9.870s

root@banshee:/data# time zfs rollback data/movies@1

real 0m0.651s

root@banshee:/data# du -hs movies

436G movies