You can get a similar effect on top of any file system that supports hard links with rdfind ( https://rdfind.pauldreik.se/ ) -- but it's pretty slow.
The Arch wiki says:
"Tools dedicated to deduplicate a Btrfs formatted partition include duperemove, bees, bedup and btrfs-dedup. One may also want to merely deduplicate data on a file based level instead using e.g. rmlint, jdupes or dduper-git. For an overview of available features of those programs and additional information, have a look at the upstream Wiki entry.
Furthermore, Btrfs developers are working on inband (also known as synchronous or inline) deduplication, meaning deduplication done when writing new data to the filesystem. Currently, it is still an experiment which is developed out-of-tree. Users willing to test the new feature should read the appropriate kernel wiki page."
> You can get a similar effect on top of any file system that supports hard links with rdfind ( https://rdfind.pauldreik.se/ ) -- but it's pretty slow.
It's a similar effect only if you don't modify the files, I think.
If you "clone" a file with a hard link and you modify the contents of one copy, the other copy would also be equally modified.
As far as I understand this wouldn't happen with this type of block cloning: each copy of the file would be completely separate, except that they may (transparently) share data blocks on disk.
The Arch wiki says:
"Tools dedicated to deduplicate a Btrfs formatted partition include duperemove, bees, bedup and btrfs-dedup. One may also want to merely deduplicate data on a file based level instead using e.g. rmlint, jdupes or dduper-git. For an overview of available features of those programs and additional information, have a look at the upstream Wiki entry.
Furthermore, Btrfs developers are working on inband (also known as synchronous or inline) deduplication, meaning deduplication done when writing new data to the filesystem. Currently, it is still an experiment which is developed out-of-tree. Users willing to test the new feature should read the appropriate kernel wiki page."