How to efficiently update a copy of a large binary file

Question

I have a large file (~20 GB, VirtualBox VM of Windows XP) that I would like to clone to a second computer and then keep synchronized, 1-way, from the primary computer.

Is there a generic way of updating only the changed parts of a binary file?

If there is not a generic tool, is there a specific way to do this for VirtualBox?

Answer 1

How about, well, rsync? It uses a block delta transfer algorithm by default.