[kwlug-disc] question -- how to backup BTRFS to another BTRFS?

[William Park]

To BTRFS experts,

I'm currently using BTRFS as on-line backup, and I'm getting used to its
snapshot capability.  Now, I would like to backup it to another BTRFS
disk and pull it out for off-line backup.  I can't use 'rsync' for this,
because it doesn't understand BTRFS snapshot and subvolume, and will
only copy as directories/files.

How do you backup up one BTRFS to another BTRFS?  Manual says something
about "send" and "receive".  Are those right keywords to search for?
-- 
William