[root@freenas ~]# zpool status
  pool: RAIDZ
 state: ONLINE
status: One or more devices has experienced an unrecoverable error.  An
        attempt was made to correct the error.  Applications are unaffected.
action: Determine if the device needs to be replaced, and clear the errors
        using 'zpool clear' or replace the device with 'zpool replace'.
   see: http://illumos.org/msg/ZFS-8000-9P
  scan: scrub repaired 13.9M in 4h46m with 0 errors on Sun Nov  2 04:47:00 2014
config:

        NAME                                            STATE     READ WRITE CKSUM
        RAIDZ                                           ONLINE       0     0     0
          raidz1-0                                      ONLINE       0     0     0
            gptid/f79eaab8-32f7-11e2-a7b0-00237d3f34e0  ONLINE       0     0     1
            gptid/f805f5fc-32f7-11e2-a7b0-00237d3f34e0  ONLINE       0     0     0
            gptid/f8abe52a-32f7-11e2-a7b0-00237d3f34e0  ONLINE       0     0     0
            gptid/f912f866-32f7-11e2-a7b0-00237d3f34e0  ONLINE       0     0     0

errors: No known data errors