ZFS pool data recovery

[Jonni Nakari]

It seems, that while testing suspend to RAM on my machine by running 
"acpiconf -s 3" I managed to break a RaidZ zpool. The machine went to 
sleep fine, but after waking up commands (e.g. reboot) reported I/O 
error. When booting after a hard reset the machine fails to mount the 
root filesystem:

Trying to mount root from zfs:/vault/root []...
Mounting from zfs:/vault/root failed with error 5.

I booted the system from FreeBSD-9.1-RELEASE-amd64-memstick.img and 
tried to import the zpool in the shell:
  # zpool import -f vault
cannot import 'vault': I/O error
     Destroy and re-create the pool from
     a backup source.

Command "zpool import -nfF vault" from the memstick system gives no 
output. (I thought it should always give some output?)

What should I try next to repair the zpool or recover the data? I 
started "zpool import -nfFX vault" but it seems to take quite long.

Some more information about my system:
zpool vault consists of 5 block devices:
whole disks: ada1, ada2, ada3
cache: ada0s1e
log: ada0s1d

The system boots from a UFS filesystem ada0s1a. The zpool and rest of 
the system was created with FreeBSD 9.1-RELEASE.

-- 
Jonni Nakari
jonni at egarden.fi