The Backup System handles data at the level of volumes rather than individual files. You must define groups of volumes called volume sets before performing backup operations, by using the backup addvolset command. A volume set name can be up to 31 characters long and can include any character other than the period (.), but avoid using metacharacters that have special meanings to the shell.

After creating a volume set, use the backup addvolentry command to place one or more volume entries in it. They define the volumes that belong to it in terms of their location (file server machine and partition) and name. Use the command's required -server argument to designate the file server machine that houses the volumes of interest and its required -partition argument to designate the partition. Two types of values are acceptable:

For the volume name (the required -volume argument), specify a combination of alphanumeric characters and one or more metacharacters to specify part or all of the volume name with a wildcard. You can use any of the following metacharacters in the volume name field:

Perhaps the most common regular expression is the period followed by an asterisk (.*). This expression matches any string of any length, because the period matches any character and the asterisk means any number of that character. As mentioned, it is the only acceptable regular expression in the file server and partition fields of a volume entry. In the volume name field, it can stand alone (in which case it matches every volume listed in the VLDB), or can combine with alphanumeric characters. For example, the string user.*\.backup matches any volume name that begins with the string user and ends with .backup.

Issuing the backup addvolentry command in interactive mode is simplest. If you issue it at the shell prompt, you must surround any string that includes a regular expression with double quotes (" ") so that the shell passes them uninterpreted to the backup command interpreter rather than resolving them.

To define various combinations of volumes, provide the following types of values for the backup addvolentry command's three arguments. The list uses the notation appropriate for interactive mode; if you issue the command at the shell prompt instead, place double quotes around any string that includes a regular expression. To create a volume entry that includes:

As you create volume sets, define groups of volumes you want to dump to the same tape at the same time (for example, weekly or daily) and in the same manner (fully or incrementally). In general, a volume set that includes volumes with similar contents (as indicated by similar names) is more useful than one that includes volumes that share a common location, especially if you often move volumes for load-balancing or space reasons. Most often, then, it is appropriate to use the regular expression .* (period followed by a backslash) for the -server and -partition arguments to the backup addvolentry command.

It is generally more efficient to include a limited number of volumes in a volume entry. Dumps of a volume set that includes a large number of volume can take a long time to complete, increasing the possibility that the operation fails due to a service interruption or outage.

To remove a volume entry from a volume set, use the backup delvolentry command. To remove a volume set and all of its component volume entries from the Backup Database, use the backup delvolset command. To display the volume entries in a volume set, use the backup listvolsets command.

By default, a Backup Database record is created for the new volume set. Sometimes it is convenient to create volume sets without recording them permanently in the Backup Database, for example when using the backup volsetrestore command to restore a group of volumes that were not necessarily backed up together (for further discussion, see Using the backup volsetrestore Command). To create a temporary volume set, include the -temporary flag to the backup addvolset command. A temporary volume set exists only during the lifetime of the current interactive session, so the flag is effective only when used during an interactive session (opened by issuing the backup (interactive) command). You can use the backup delvolset command to delete a temporary volume set before the interactive session ends, if you wish, but as noted it is automatically deleted when you end the session. One advantage of temporary volume sets is that the backup addvolset command, and any backup addvolentry commands subsequently used to add volume entries to it, complete more quickly than for regular volume sets, because you are not creating any Backup Database records.