ZFS pool 'strawberry' expanded with a relatively small disk

[root@freenas] ~# date && uname -a
Sun Jan 31 05:48:28 GMT 2016
FreeBSD freenas.local 9.2-RELEASE-p9 FreeBSD 9.2-RELEASE-p9 #0 r262572+cc525fe: Thu Jul  3 14:22:45 PDT 2014     root@build3.ixsystems.com:/fusion/jenkins/9.2.1.6-RELEASE/os-base/amd64/fusion/jenkins/9.2.1.6-RELEASE/FreeBSD/src/sys/FREENAS.amd64  amd64
[root@freenas] ~# gpart show
=>       63  625142385  ada0  MBR  (298G)
         63    1930257     1  freebsd  [active]  (942M)
    1930320         63        - free -  (31k)
    1930383    1930257     2  freebsd  (942M)
    3860640       3024     3  freebsd  (1.5M)
    3863664      41328     4  freebsd  (20M)
    3904992  621237456        - free -  (296G)

=>      0  1930257  ada0s1  BSD  (942M)
        0       16          - free -  (8.0k)
       16  1930241       1  !0  (942M)

=>      0  1930257  ada0s2  BSD  (942M)
        0       16          - free -  (8.0k)
       16  1930241       1  !0  (942M)

=>       34  312581741  ada2  GPT  (149G)
         34         94        - free -  (47k)
        128    4194304     1  freebsd-swap  (2.0G)
    4194432  308387336     2  freebsd-zfs  (147G)
  312581768          7        - free -  (3.5k)

=>        34  5860533101  ada3  GPT  (2.7T)
          34          94        - free -  (47k)
         128     4194304     1  freebsd-swap  (2.0G)
     4194432  5856338696     2  freebsd-zfs  (2.7T)
  5860533128           7        - free -  (3.5k)

[root@freenas] ~# zpool list -v
NAME                                     SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
strawberry                               611G   495G   116G    81%  1.00x  ONLINE  /mnt
  ada1                                   464G   453G  11.1G         -
  gptid/bcc4af50-c5ff-11e5-b19e-001cc0bf031a   147G  42.2G   105G         -
tallhalf                                2.72T   213G  2.51T     7%  1.00x  ONLINE  /mnt
  gptid/867f6402-c5ef-11e5-81b7-001cc0bf031a  2.72T   213G  2.51T         -
[root@freenas] ~# zpool status
  pool: strawberry
 state: ONLINE
status: The pool is formatted using a legacy on-disk format.  The pool can
	still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'.  Once this is done, the
	pool will no longer be accessible on software that does not support feature
	flags.
  scan: scrub repaired 0 in 9h12m with 0 errors on Thu Jan 28 08:01:08 2016
config:

	NAME                                          STATE     READ WRITE CKSUM
	strawberry                                    ONLINE       0     0     0
	  ada1                                        ONLINE       0     0     0
	  gptid/bcc4af50-c5ff-11e5-b19e-001cc0bf031a  ONLINE       0     0     0

errors: No known data errors

  pool: tallhalf
 state: ONLINE
  scan: scrub repaired 0 in 0h45m with 0 errors on Sat Jan 30 13:21:43 2016
config:

	NAME                                          STATE     READ WRITE CKSUM
	tallhalf                                      ONLINE       0     0     0
	  gptid/867f6402-c5ef-11e5-81b7-001cc0bf031a  ONLINE       0     0     0

errors: No known data errors
[root@freenas] ~#