When it comes to the BSD operating systems, DragonFlyBSD's HAMMER2 is one of the most interesting innovations. HAMMER2 supports online deduplication, clustering, multiple mountable file-system roots, snapshots, compression, encryption, extensive checksumming, and other features. Over the past decade it's evolved quite nicely and in recent days has seen further enhancements.

DragonFlyBSD lead developer Matthew Dillon has recently been working on further refinements to HAMMER2 for the next DragonFlyBSD operating system release.

The latest HAMMER2 activity in the past few days has included improving its CPU performance and adding a new "hammer2 recover" directive. The HAMMER2 recover support allows for recovering/undoing single files as well as preliminary support to recover entire directory structures.

Those interested in more details on the HAMMER2 recovery support and the performance optimizations can see the recent HAMMER2 commits to the DragonFlyBSD Git.