I regularly use
btrfs send and
btrfs receive to copy read-only snapshots from my live system to a backup drive. On the backup drive there are already multiple snapshots. Today I wondered: Can I copy multiple of today's snapshots as incremental update from multiple older snapshots at once?
Recently I did
btrfs send -p home_old home_today | btrfs receive /mnt/backup/ btrfs send -p share_old share_today | btrfs receive /mnt/backup/
Could this be unified to 1 command?
So I looked into
man btrfs-send and read:
In the incremental mode (options -p and -c), previously sent snapshots that are available on both the sending and receiving side can be used to reduce the amount of information that has to be sent to reconstruct the sent snapshot on a different filesystem.
That's what I want.
send an incremental stream from parent to subvol
use this snapshot as a clone source for an incremental send (multiple allowed)
It seems that only one of
-c supports multiple existing snapshots but I don't get the difference between them. What's the difference?