Backups rarely get tested and when they get tested they
sometimes fail.
So I propose a solution: A program is configured to write
its
files through a driver*. The driver decides where to save
and
open files from.
Every time the application is shut down, the file system
driver makes
a backup and then when the software is re-
opened it switches to a backup location and reads and
writes from there.
This way your backup media gets tested.
*FUSE or Windows
Or Windows File system proxy
https://github.com/billziss-
gh/winfsp