GlusterFS (GFS) is the open source equivalent to Microsoft's Distributed Filesystem (DFS). It's a service that replicates the contents of a filesystem in real time from one server to another. Clients connect to any server and changes made to a file will replicate automatically. It's similar to something like rsync or syncthing, but much more automatic and transparent. A FreeBSD port has been available since v3.4, and (as of this post) is currently at version 8.0 with 9.0 being released soon.
This is a technology demonstration and tutorial for deploying GlusterFS on FreeBSD. As a bonus this is an opportunity to play with Bhyve.