When creating backups, you copy groups of filesets, known as fileset families, to tape. A fileset family includes all of the filesets that you want to dump together onto the same tape (or tapes, if the fileset family contains a large number of filesets). All of the filesets in a fileset family are dumped to tape with the same frequency (for example, once a day or once a week).
Fileset family entries (also referred to as fileset entries) define the filesets included in a fileset family. Each entry has three fields: the File Server machine name, the aggregate name, and the fileset name. Because filesets can be moved from File Server to File Server, the first two fields are usually designated with a .* wildcard, so a person backing up the filesets does not need to know the File Server machine and aggregate on which they reside. The last field, fileset name, is often specified with a regular expression pattern that matches certain fileset names.
Within the Backup System, regular expression characters and the .* wildcard can be used in many arguments. (See Defining Fileset Families and Fileset Family Entries for a description of these characters and their interpretations.)