[root@freenas] ~# zpool status
  pool: alex1
 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://www.sun.com/msg/ZFS-8000-2Q
  scan: none requested
config:

        NAME                                            STATE     READ WRITE CKSUM
        alex1                                           DEGRADED     0     0     0
          raidz1-0                                      DEGRADED     0     0     0
            gptid/a764ebb9-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            gptid/a7f364b3-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            gptid/a88576f8-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            gptid/a910c482-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            6075023609475281399                         UNAVAIL      0     0     0  was /dev/dsk/gptid/586511a6-1148-11e2-9afd-000c292abc5c
            gptid/aa3b7253-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            gptid/aacc6413-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0
            gptid/ab653978-b1ba-11e1-b4e1-000c292abc5c  ONLINE       0     0     0

errors: No known data errors