Patent ID: 8856450

Claim:
A system, comprising: a virtual tape library having a cache; at least one virtual tape controller coupled to the virtual tape library; and an interface for coupling at least one host to the at least one virtual tape controller, wherein the cache is shared by the at least one host, wherein a common view of a cache state, a virtual library state, and a number of write requests pending is provided to the at least one host by the virtual tape controller, wherein the at least one virtual tape controller enters into a warning state and provides a first alert to the at least one host when a cache free space size is less than a first threshold, wherein the at least one virtual tape controller enters into a critical state and provides a second alert to the at least one host when a cache free space size is less than a second threshold, wherein the at least one virtual tape controller is configured to delete at least one scratch volume when in the critical state, the scratch volume chosen based on at least one of: a length of time the scratch volume has been designated scratch, a priority level of the information stored on the scratch volume, and a scratch delay value associated with the scratch volume.