Automatically calculate the number of tapes or diskettes needed for backing up file systems 

You can use the dry run mode (S option) to determine the amount of space that is needed before actually backing up file systems. 

Provide built-in error checking to minimize problems when backing up an active file system 

-- 

Enable you to back up files that are remotely mounted from a server 

Files on the server must be backed up on the server itself. Users are denied permission to run ufsdump on files they own that are located on a server.