There are a couple, a web server (it doesn't have much on it), but the database server and the FTP server do. Even scheduling the full back ups during off hours I still need to do incrementals during business hours and they put a big dent in my bandwidth when they run, even though it is just a few minutes.
And yes, I know the DB server should not be in the DMZ, but I inherited this and can't fix it right now.