[CentOS] block level changes at the file system level?

Thu Jul 3 19:05:19 UTC 2014
Jack Bailey <jack at internetguy.net>

>> I think the buzzword you want is dedup.
> dedup works at the file level. Here we're talking about files that are
> highly similar but not identical. I don't want to rewrite an entire file
> that's 99% identical to the new file form, I just want to write a small
> set of changes. I'd use ZFS to keep track of which blocks change over time.
>
> I've been asking around, and it seems this capability doesn't exist
> *anywhere*.

Check this link.

https://blogs.oracle.com/bonwick/entry/zfs_dedup

...

*What to dedup: Files, blocks, or bytes?*

Data can be deduplicated at the level of files, blocks, or bytes.
...