Delete only run

[Fabian Cenedese]

Hi

I have a backup on a NAS that is quite full. So when I try to backup
changed stuff it may run out of space, but only because rsync may
try to write a new file before deleting the old one. That not only means
changed files in the same place but also moved files, so delete-before
wouldn't help.

Is there a possibility to have a complete rsync run that only deletes
files to make space for the new files being synched in a second run?
Could this be done with the batch mode and some file sorting?

Thanks

bye  Fabi