how to backup

Hello,

Say I have a btrfs-formatted disk with many subvolumes/snapshots.

How do I do backup (over network) ?

If I use just rsync, I will get many copies of the files (one for each snapshot).

So I would need to write a tool that would
- get listing of the subvolumes/snapshots
- somehow figure out which is which (snapshot of what is this one)
- somehow recursively create the subvolume, copy data, snapshot it, copy data etc.?

Thank you for your suggestions

Lubos