I have a related follow-up to this. It's not an exact match but I'm not sure if it warrants its own thread (and this is the closest thread I could find to it).
If one is running FreeBSD as just a basic home Windows/Samba file server, with the basic install OS on a flash drive (everything else on HDDs), and one has no other UNIX-based systems in the house, is the above the best way to approach backing up the flash drive/OS? If so, this relates directly to the live backup OP.
Or is there another way, such as taking an offline backup/snapshot by sticking the flash into a Windows PC and somehow making an image of it to be the replacement when the flash drive dies? On the surface, this sounds easier (given the OS drive can move freely, the mostly static nature of the OS data, and the Windows env) but I don't know if it's even possible.
BTW, one = me, of course. But I'd think I'm not the only one.