Matthew Dillon has announced the next version of DragonFly BSD's new HAMMER file system will soon be available for testing. HAMMER supports modern file system features such as snapshots, deduplication and data checksums to protect against file corruption. The new version of HAMMER will not be an install option in the next release of DragonFly BSD, but the technology will be available for people to test. "The next DragonFly release (probably in September some time) will have an initial HAMMER2 implementation. It will be considered experimental and won't be an installer option yet. This initial release will only have single-image support operational plus basic features. It will have live dedup (for cp's), compression, fast recovery, snapshot, and boot support out of the gate. This first H2 release will not have clustering or multi-volume support, so don't expect those features to work. I may be able to get bulk dedup and basic mirroring operational by release time, but it won't be very efficient. Also, right now, sync operations are fairly expensive and will stall modifying operations to some degree during the flush, and there is no reblocking (yet). The allocator has a 16KB granularity (on HAMMER1 it was 2MB), so for testing purposes it will still work fairly well even without reblocking. The design is in a good place. I'm quite happy with how the physical layout turned out." More details can be found in Dillon's mailing list post.