Ever have that gut feeling of dread when you realize that you don't have a complete backup, or maybe no backup at all?
Remember that feeling?
3 copies of data. At least one "remote".
sdxc card on your person when you go out.
encypted partition on friends computer in another country, and you host their partition.
global distributed.
1) Sync.
Sync is not backup. Your Sync can be infected/encrypted too, because it's connected ... so that you can , you know, sync.
Sync the data in as near to realtime is useful to you.
But realize that sync is not backup, so ...
What if I lose the last 10 mins? The last 10 hours?
2) Backup over the Network.
But *PULL* your backups to the target machine. Do not PUSH them to the target. Why? Push requires write permissions, but PULL only requires read permissions.
Still, this relies on permsissions not being hacked. It is possible that the permissions can be bypassed.
Therefore, have an air-gapped backup too, even if it's just pushing the sdxc card in to the slot before you put it in your pocket and go somewhere else.
Scale up to global distributed backups.