ZFS or btrfs in most places. All devices with snapshotting capabilities, keep hourly, daily, weekly, monthly snapshots. Once per day, all devices rsync their

ZFS or btrfs in most places. All devices with snapshotting capabilities, keep hourly, daily, weekly, monthly snapshots. Once per day, all devices rsync their /home to NAS. (I would use ZFS send/receive, but I want more selective backups.) NAS also keeps snapshots. A daily snapshot of the most critical data is encrypted and sent off to an offsite server. Hadn't lost a single byte in years (since shortly before implementing this scheme :P).