[ceph-users] Semantics of cephfs-mirror

Dear all, I'm sorry if I'm asking for the obvious or missing a previous discussion of this but I could not find the answer to my question online. I'd be happy to be pointed to the right direction only. The cephfs-mirror tool in pacific looks extremely promising. How does it work exactly? Is it based on files and (recursive) ctime or rather based on object information? Does it handle incremental changes (only) between snapshots? There is an issue related to this that mentions recursive ctime. But that would mean that users could "rsync -a" data to the file system and this would not get synchronized. I have good experience with ZFS which is able to identify changes between two snapshots A and B and then only transfer these changes (using a sub-file level, on the ZFS equivalent of blocks to my understanding) to another server with the same file system that is in the exact state as snapshot A. Does cephfs-mirror work the same? Best wishes, Manuel