System and method to guarantee overwrite of expired data in a virtual tape server

A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform a method for guaranteeing overwrite of data stored in a media device when the data has expired, wherein the data is organized in logical units provided on the media device, and the media device is organized in respective physical volumes, said method comprising:

• a) maintaining status information associated with each respective physical volume, and updating the status information of each respective physical volume based on a prior status and a current status thereof to provide updated status information;
• b) specifying a time duration in which expired data may remain on each respective physical volume;
• c) based upon the updated status information thereof, determining whether a selected one of the physical volumes has data that has been expired for a duration that is longer than the specified time duration thereof;
• d) adding the at least a selected one of the physical volumes to a list of physical volumes to be overwritten when it is determined in the step c) that the at least a selected one of the physical volumes has the data that has been expired for the duration that is longer than the specified time duration;
• and
• (e) overwriting contents, including the expired data, of physical volumes on the list of physical volumes to be overwritten so that the expired data thereof cannot be read by the media device.

A virtual tape storage system comprising a tape media device for storing user data organized in logical wilts provided on the tape media device, the tape media device organized in respective physical volumes, said system comprising:

• a) a host system interface for receiving a user instruction that specifies a time duration in which expired data for the user may remain on each respective physical volume;
• b) a control device for maintaining status information associated with each respective physical volume, and updating the status information of each respective physical volume based on a prior status and a current status thereof to provide updated status information;
• c) means for determining, based on the updated status information thereof, whether a selected one of the respective physical volumes has data that has been expired fur a duration that is longer than the specified time duration thereof;
• and,
• d) means fur adding the at least a selected one of the physical volumes to a list of physical volumes to be overwritten when it is determined by the means for determining that the at least a selected one of the physical volumes has the data that has been expired for the duration that is longer than the specified time duration;
• and,
• e) means for overwriting contents, including the expired data, of physical volumes on the list of physical volumes to be overwritten so that the expired data thereof cannot be read by the tape media device.