Hi consider this situation:
you have a large filesystem and want to do a backup. normally you don't want to use rsync with CRC check because of many calculation that should be done because of CRC calculation. but with modification time and size option some files that didn't really changed are backuped again (I don't know why!)
is it possible to tell to rsync to first do a check for modification time and size and among those files(that rsync diagnosed as different in modification time or size) do a crc check?