I have 6 devices that i rsync to a central location to back them up. Ive been using ssh as the -e option. Problem is i use public key with passphrases, meaning to backup all six i need to go to each device and run the backup script. Since i typically backup /etc, /home, and /root this means entering sudo and the ssh passphrase 3x for each device.
I would much prefer a script that runs on back storage device that can pull the data from each device without having to use ssh (encryption is not necessary since all traffic is either local or going through a vpn connection).
I could then put this script in root’s crontab or make it a systemd service running as root.
But i dont know how i can remote sync without ssh
I guess the Btrfs snapshopt approach is not possible for your setup since the devices you want to backup are not Btrfs and cannot create snapshots.
Yes, the snapshots will be the size of the whole partition, I had not thought about that problem. I do not know if it is possible to create incremental snapshots with Btrfs.