It means files remote-server-ip were either deleted or modified by someone/process. Hence you see the warning. Usually this can be fixed running the rsync command again. There is no command option to prevent this kind of issues.
ignore “vanished files” warning
Some folks would like to ignore the “vanished files” warning, which manifests as an exit-code 24. The easiest way to do this is to create a shell script wrapper. For instance, name this something like “rsync-no24”:
if test $e = 24; then
Taken from here
suppress rsync warning: some files vanished before they could be transferred
Use exclude syntax to ignore dynamically changing files in a given directory.
rsync -avz --exclude '/path/to/dir' user@source:/dest/
See rsync command man page by typing the following command: