So my the USB drive attached to my FreeNas 7 system, went bad so I used the situation as an opportunity to upgrade to FreeNas 8. The problem is now I'm having trouble getting my ZFS to spin up:
[root@media] ~# zpool import
  pool: filetank
    id: 17702465758427828599
 state: FAULTED
status: The pool was last accessed by another system.
action: The pool cannot be imported due to damaged devices or data.
    The pool may be active on another system, but can be imported using
    the '-f' flag.
   see: http://www.sun.com/msg/ZFS-8000-EY
config:
    filetank    FAULTED  corrupted data
      raidz1    FAULTED  corrupted data
        ada3    ONLINE
        ada1    ONLINE
        ada4    ONLINE
        ada2    ONLINE
[root@media] ~# zpool import -f filetank
cannot import 'filetank': one or more devices is currently unavailable
What's weird is that just the raidz says its corrupted and I'm not sure what to do about it. Most stuff I can find involves replacing an individual device, but it doesn't look like any particular device has failed? I went back to FreeNas 7 and got the same error, which is basically what I expected.