DragonFly BSD 5, a fork of FreeBSD (or possibly real FreeBSD and the current FreeBSD is the fork, that's semantics) has released. The big news with DFBSD5 is that the Hammer2 filesystem has finally released with it. Hammer has long been one of the more advanced filesystems on the market and Hammer2 is a major update to it.
Hammer2 currently supports live dedupe, compression, fast recovery and snapshots. Multi-volume and clustering are not yet available, but are coming.