We can not use --link-dest when doing the dryrun as it will consider
everything up to date. So create some base args and then add the right
parts to it. Skip --checksum from the cli as it makes things really
slow. Use rsync (instead of diff -r) as this will be used for the final
handling. Keep on using sub dirs as this gives higher control. We could
otherwise just syncrhonize everything.
This is not tested and will be debugged on the server. Begin to
automate the on-server setup so we can make this a self-service
without much user interaction.
Holger Hans Peter Freyther