ZFS Tuning

Check Arc Memory Usage
# echo ::memstat|mdb -k
Page Summary                Pages                MB  %Tot
------------     ----------------  ----------------  ----
Kernel                     525663              4106    6%
ZFS File Data             5375945             41999   64%              <--- ZFS ARC Cache
Anon                      1641742             12826   20%
Exec and libs               35704               278    0%
Page cache                 531177              4149    6%
Free (cachelist)           121617               950    1%
Free (freelist)            156760              1224    2%
Total                     8388608             65536

to limit ZFS ARC Cache size, add/modify below line in /etc/system (it will take effect after next reboot)

set zfs:zfs_arc_max=6442450944

References:
http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide
http://docs.oracle.com/cd/E26502_01/html/E29022/chapterzfs-1.html#scrolltoc