Local backup (NAS with snapshots), and back up to cloud - Backblaze, Amazon, Carbonite, Crashplan etc.
The solution must consider the possibilities:
- Cryptolocker style ransomware encrypting everything on your network, including unmapped drives and a connected NAS (
https://forum.synology.com/enu/viewt...?f=108&t=88770)
- Someone breaking in to your house and stealing everything. Does it need to be encrypted?
- Restore time - possibly limited to the speed of your Internet connect, but possibly the remote servers might be the bottleneck.
- Try to reduce the chance of needing to restore from remote backups in the first place. RAID on your NAS, snapshots turned on, use OS software restriction policies, keep your browser, Flash and Reader etc up-to-date (or uninstall them!), use NoScript and an adblocker, etc.