Hammer2 offline deduplication

[Mikhail Novosyolov]

Hi,

I have not been able to find documentation about how deduplication works 
in Hammer2. I have only found that online deduplication is now on by 
default, but there seems to be no description how it works.

Is it possible to make offline deduplication? I mean finding blocks with 
the same checksum and making one block point to another instead of 
spending space on disk twice? There are several utilities that do this 
on BTRFS in Linux, for example https://github.com/Zygo/bees