ZFS failed after hard power off

[Piotr Paczynski]

Hi all,

I urgently need help. After hard power-off (power cable disconnected)
my FreeBSD 8.1-STABLE server fails to boot from ZFS with an I/O Error.
I was able to boot to Fixit console from 8.2 LiveFS, prepare it for
ZFS and mount the pool using "zpool import -Ff" command. Here are the
results:

Fixit# zpool status
  pool: zroot
 state: FAULTED
status: The pool metadata is corrupted and the pool cannot be opened.
action: Destroy and re-create the pool from a backup source.
   see: http://www.sun.com/msg/ZFS-8000-72
 scrub: none requested
config:
        NAME         STATE   READ WRITE CKSUM
        zroot        FAULTED    0     0     1 corrupted data
          gpt/array0 ONLINE     0     0     6

Also "zdb -l /dev/gpt/array0" shows 4 LABELS. Each has the same
attributes, in particular:
  version=14
  state=0
  txg=4

Here are the screen-shots in case I missed something:
https://picasaweb.google.com/113032262178118660549/ZfsFailure#

Any pointers how to go about recovering data from this pool anyone?

-- 
Piotr Paczynski