On individual nodes I keep data in specific directories away from the OS. I rsync those directories to a machine that acts like a NAS. That machine uses rsnap

On individual nodes I keep data in specific directories away from the OS. I rsync those directories to a machine that acts like a NAS. That machine uses rsnapshot to have multiple file level diffs uses hardlinks to save space on dupe files. I back that up to multiple external SSD USB drives. I have one drive in my vehicle. Encryption is just plain dm-crypt with non default cipher/hash, no LUKS headers.