Currently, rsync doesn't allow mixing different kinds of basis dirs (e.g., a --compare-dest dir and a --link-dest dir) on the same run. This restriction seems excessive; I would like it relaxed. I'm not sure exactly what combinations would make sense or be useful, so let's discuss it here. See also this thread: http://lists.samba.org/archive/rsync/2007-February/017311.html At a minimum, I think it should be possible to add any number of optimization-only --copy-dest and/or --link-dest dirs (bug 5645) to one of the currently allowed configurations. This would provide an alternative to --recheck-basis-dirs (bug 5644) for the scenario in the following thread: http://lists.samba.org/archive/rsync/2008-July/021400.html