I make no endorsements because I have not tried not but this looks oh so promising.

What is DeltaCopy
In general terms, DeltaCopy is an open source, fast incremental backup program. Let's say you have to backup one file that is 500 MB every night. A normal file copy would copy the entire file even if a few bytes have changed. DeltaCopy, on the other hand, would only copy the part of file that has actually been modified. This reduces the data transfer to just a small fraction of 500 MB saving time and network bandwidth.

In technical terms, DeltaCopy is a "Windows Friendly" wrapper around the Rsync program, currently maintained by Wayne Davison. "rsync" is primarily designed for Unix/Linux/BSD systems. Although ports are available for Windows, they typically require downloading Cygwin libraries and manual configuration. ...

NOTE: If you have an "rsync" daemon running on Linux/Unix/BSD or any other platform, DeltaCopy client will successfully connect to them.

Don't worry, a review will be forthcoming. But if you want to write it sign up for Wizbang Tech and share your thoughts on it.