ZFS is a relatively new and exciting file storage system developed by Sun.
The features of ZFS include support for high storage capacities, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs. – Wikipedia
This page has some specific FreeBSD info relating to ZFS.
Interested to find out more about the strengths of ZFS? Have a look at the video’s below: