[hikarudo]

> I've been thinking about solving the backup part by letting one of the devices perform btrfs snapshots on its storage.

I do zfs snapshots on my storage server (home desktop), which is in Syncthing's "receive only" mode. I use it to sync my camera roll and Whatsapp media files from my Android phone. I use pyznap for snapshot management.

> Setting up a cron job / timer unit that commits the synced folder to a git repo is also an alternative

Another option would be to backup the synced folder using a backup tool like borg, restic, duplicacy etc. They have options to prune the snapshots.

[andrewaylett]

I have a script that takes a btrfs snapshot, uses borg to back up the consistent snapshot (to rsync.net), then removes the snapshot again. It then instructs Borg about which snapshots to retain, so my space shouldn't grow without bound.

For extra extra snapshotting fun, rsync.net then takes ZFS snapshots of the borg backup. So even if my snapshot cleaning gets over-enthusiastic, I'll still have a snapshot of the snapshot.