Yeah, most of the approaches to trashing ZFS are along similar lines: get it to tie itself in knots and use 75% system CPU trying to get itself sorted out. "With you in a moment ... a moment ... a moment ..." The famed killer ZFS block allocator bug (lots of small fast writes to a large zpool that's over 80% full, block allocator shits itself trying to allocate perfectly rather than well enough, box turns to molasses, requires reboot, workaround is to leave 25% of your huge expensive zpool empty) is one of these.