TLDR: VSS support for BTRFS filesystem would be great to have.
Longer version: I’m running duplicacy on a Synology DSM. I felt a bit uneasy about live backup without snapshotting but was’t really giving it too much thought.
It just recently occurred to me that the native backup solution on those devices – HyperBackup – does take a snapshot before backing up; which is a good indication that this use case it polished to death on those appliances.
It would be therefore really awesome if duplicacy supported that.
Snapshotting on a BTRFS is fairly trivial. You would mount the volume somewhere, and then when done – delete it (no dance around tmutil like on a Mac :))
ash-4.3# mkdir /volume1/Data/_snp0000001 ash-4.3# btrfs subvolume snapshot -r /volume1/homes /volume1/Data/_snp0000001 Create a readonly snapshot of '/volume1/homes' in '/volume1/Data/_snp0000001/homes' ash-4.3# #Do the thing ash-4.3# btrfs subvolume delete -c /volume1/Data/_snp0000001/homes Delete subvolume (commit): '/volume1/Data/_snp0000001/homes' ash-4.3# rm -r /volume1/Data/_snp0000001
As a prerequisite the user duplicacy is running under should be added to the sudoers file to allow btrfs utilities.