[root@freenas ~]# zpool status
  pool: FreeNasStorage
 state: DEGRADED
status: One or more devices could not be opened.  Sufficient replicas exist for
        the pool to continue functioning in a degraded state.
action: Attach the missing device and online it using 'zpool online'.
   see: http://illumos.org/msg/ZFS-8000-2Q
  scan: scrub in progress since Sat Jul 21 11:18:10 2018
        54.1M scanned out of 30.3T at 89.7K/s, (scan is slow, no estimated time)
        0 repaired, 0.00% done
config:

        NAME                                            STATE     READ WRITE CKSUM
        FreeNasStorage                                  DEGRADED     0     0     0
          raidz1-0                                      DEGRADED     0     0     0
            gptid/9735eeb9-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/98976049-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/99d5d6e9-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/9ad2b7c0-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/9bf206f5-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/9d57bc7a-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            3386550101567640421                         UNAVAIL      0     0     0  was /dev/gptid/9ee95243-dd2d-11e7-9393-782bcb2ca
227
            gptid/a040ac5b-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/a1954532-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/a2e25b7b-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/a45475bb-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0
            gptid/a596ae03-dd2d-11e7-9393-782bcb2ca227  ONLINE       0     0     0

errors: No known data errors

  pool: freenas-boot
 state: ONLINE
  scan: scrub repaired 0 in 0h1m with 0 errors on Sat Jul 21 03:46:12 2018
config:

        NAME        STATE     READ WRITE CKSUM
        freenas-boot  ONLINE       0     0     0
          mirror-0  ONLINE       0     0     0
            da13p2  ONLINE       0     0     0
            da14p2  ONLINE       0     0     0

errors: No known data errors