bdsync

This is a useful utility for synchronising large files, or entire block devices, over a network.

It is invoked from the machine with the source file (or block device). A patch file is generated, and this patch file can be copied to the remote machine and applied to restore the file as it is on the source machine.

bdsync --progress "ssh remote_server bdsync --server" local_file remote_file > patch_file