Ilya Dryomov’s work on deduplication for Hammer has been committed to the tree in an early test form.  I guess I need to pay up as part of the code bounty.  If you’re wondering how much space it will save, but don’t want to try non-production code yet, there’s a ‘hammer dedup-simulate’ command that will estimate the saving ratio.

This is great news – deduplication is so valuable it adds an extra zero onto the price of any storage device that can do it.