カーネルも安定して動いているので、FreeBSD ZFSのpool versionを13から14にあげた。
guriandgura# zpool status -v
  pool: tank
 state: ONLINE
status: The pool is formatted using an older 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 older software versions.
 scrub: none requested
config:

	NAME            STATE     READ WRITE CKSUM
	tank            ONLINE       0     0     0
	  raidz1        ONLINE       0     0     0
	    ad6s2       ONLINE       0     0     0
	    ad8s2       ONLINE       0     0     0
	    ad10s2      ONLINE       0     0     0
	logs            ONLINE       0     0     0
	  label/zil     ONLINE       0     0     0
	cache
	  label/zcache  ONLINE       0     0     0

errors: No known data errors
guriandgura# zpool upgrade -v
This system is currently running ZFS pool version 14.

The following versions are supported:

VER  DESCRIPTION
---  --------------------------------------------------------
 1   Initial ZFS version
 2   Ditto blocks (replicated metadata)
 3   Hot spares and double parity RAID-Z
 4   zpool history
 5   Compression using the gzip algorithm
 6   bootfs pool property
 7   Separate intent log devices
 8   Delegated administration
 9   refquota and refreservation properties
 10  Cache devices
 11  Improved scrub performance
 12  Snapshot properties
 13  snapused property
 14  passthrough-x aclinherit support
For more information on a particular version, including supported releases, see:

http://www.opensolaris.org/os/community/zfs/version/N

Where 'N' is the version number.
guriandgura# zpool get all tank
NAME  PROPERTY       VALUE       SOURCE
tank  size           1.94T       -
tank  used           1.42T       -
tank  available      528G        -
tank  capacity       73%         -
tank  altroot        -           default
tank  health         ONLINE      -
tank  guid           10449242002448667042  -
tank  version        13          local
tank  bootfs         -           default
tank  delegation     on          default
tank  autoreplace    off         default
tank  cachefile      -           default
tank  failmode       wait        default
tank  listsnapshots  off         default
guriandgura# zpool upgrade -a
This system is currently running ZFS pool version 14.

Successfully upgraded 'tank'

guriandgura# zpool get all tank
NAME  PROPERTY       VALUE       SOURCE
tank  size           1.94T       -
tank  used           1.42T       -
tank  available      528G        -
tank  capacity       73%         -
tank  altroot        -           default
tank  health         ONLINE      -
tank  guid           10449242002448667042  -
tank  version        14          default
tank  bootfs         -           default
tank  delegation     on          default
tank  autoreplace    off         default
tank  cachefile      -           default
tank  failmode       wait        default
tank  listsnapshots  off         default
guriandgura# zpool status -v
  pool: tank
 state: ONLINE
 scrub: none requested
config:

	NAME            STATE     READ WRITE CKSUM
	tank            ONLINE       0     0     0
	  raidz1        ONLINE       0     0     0
	    ad6s2       ONLINE       0     0     0
	    ad8s2       ONLINE       0     0     0
	    ad10s2      ONLINE       0     0     0
	logs            ONLINE       0     0     0
	  label/zil     ONLINE       0     0     0
	cache
	  label/zcache  ONLINE       0     0     0

errors: No known data errors
guriandgura#