When important files are changed, IBM Continuous Data Protection (CDP) will make an immediate local copy of the file (so you're protected even if not on a network) and will schedule another copy to go to some off-machine target. Which can be a USB disk, a file server / NAS, an internet provider, etc.

IBM Tivoli Continuous Data Protection for Files is the Shareware version. The full version can be purchased by clicking on the "CLICK HERE TO ORDER" button below for around 35.00USD.