I perform a backup once a week from my main desktop to a HDD, then once a month I copy important data/files from all nodes (proxmox, rpi’s and main desktop) to 2 “cold” unplugged HDD that’s the only time I connect them. I do all of that using rsync with backup.sh and coldbackup.sh
I use syncthing for notes across mobile/desktop/notebook, for that and other important files the backup goes to Google Drive or MEGA (besides the offline backup).
I want to try S3 Glacier since is cheaper for cloud backup… has anyone tried?