One other possible solution is Veeam Backup Agent (free). This will do a full system backup with bare metal restore. You can back up to a NAS, Veeam B&R Server ($$), or other network storage device. If you have a system failure, you boot from the linux boot cdrom, connect to your storage device and then restore your system. This is one way to protect your fog server. There may be native (Ubuntu) options like Bacula too.