Ported from BE:
An occasional need has come up to do an rsync when only the source or
destination can be mounted at once; not both. This is a pretty obscure
scenario and I'm not aware of any built in support in rsync for this
(though this should be investigated). This could probably be supported
with relatively little pain by repeated partial syncing through a
temporary location. I haven't clearly thought this through, but I think
it could easily be scripted.
Ported from BE: An occasional need has come up to do an rsync when only the source or destination can be mounted at once; not both. This is a pretty obscure scenario and I'm not aware of any built in support in rsync for this (though this should be investigated). This could probably be supported with relatively little pain by repeated partial syncing through a temporary location. I haven't clearly thought this through, but I think it could easily be scripted.