Backup Command Reference Backup Command Reference backup setexp Purpose Sets the expiration date for existing dump levels. The backup setexp command sets or changes the expiration date associated with each specified dump level, which must already exist in the dump hierarchy.
All dumps made at a dump level inherit the level's expiration date.
The Backup System refuses to overwrite a tape until all dumps in the dump set to which the tape belongs have reached their expiration date, unless the operator uses the backup labeltape to relabel the tape. If the expiration date predates the dump creation date, the Backup System immediately treats the dump as expired. When the Backup System creates a dump at the dump level, it calculates an actual expiration date by adding the relative date to the start time of the dump operation. If the command is used to change an existing expiration date associated with a dump level, the new date applies only to dumps created after the change. Existing dumps retain the expiration date assigned at the time they were created.