# US 2012/0084499 A1 · Systems and methods for managing a virtual tape library domain > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0084499 A1 - Document ID: US20120084499A1 - Status: Published application - Kind: A1 - Application number: 12/894,613 - Filed: 2010-09-30 - Published: 2012-04-05 - Earliest claimed: 2010-09-30 - Assignees: International Business Machines Corporation - Inventors: Norie IWASAKI; Katsuyoshi KATORI; Hiroyuki MIYOSHI; Takeshi NOHTA; Eiji TOSAKA - Web page: https://patentgrep.com/patent/US20120084499A1 ## CPC - G06F 3/0617: {in relation to availability} - G06F 3/0652: {Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket} - G06F 3/0686: {Libraries, e.g. tape libraries, jukebox} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Systems and methods for managing a virtual tape library (VTL) domain capable of being coupled to a host are provided. One system includes a plurality of VTL nodes configured to store multiple scratch erased volumes. Each VTL node comprises a processor configured to perform at least a portion of the below method. One method includes receiving a request from the host to de-mount a volume in one of the plurality of VTL nodes, transferring the volume to a scratch category in response to receiving the request, erasing data in the volume and categorizing the volume as a scratch erased volume, and providing ownership of the scratch erased volume to a VTL node in the plurality of VTL nodes based on pre-determined criteria for the plurality of VTL nodes. Also provided are computer storage mediums including computer code for performing the above method. ## Claims ### Claim 1 A system for managing a virtual tape library (VTL) domain capable of being coupled to a host, comprising: a plurality of VTL nodes configured to store a plurality of scratch erased volumes and capable of being coupled to the host, wherein each VTL node comprises: a processor configured to be coupled to the host, wherein each processor is configured to: receive a request from the host to de-mount a volume in one of the plurality of VTL nodes; transfer the volume to a scratch category in response to receiving the request; erase data stored in the volume and categorize the volume as a scratch erased volume; and provide ownership of the scratch erased volume to a VTL node in the plurality of VTL nodes based on pre-determined criteria for the plurality of VTL nodes. ### Claim 2 (depends on 1) The system of claim 1, wherein each processor is further configured to: compare a number of scratch erased volumes owned by each VTL node with a predetermined threshold number of scratch erased volumes; and provide the ownership to the VTL node based on the comparison. ### Claim 3 (depends on 2) The system of claim 2, wherein the VTL node owns less than the predetermined threshold number of scratch erased volumes. ### Claim 4 (depends on 3) The system of claim 3, wherein the VTL node owns a least amount of scratch erased volumes relative to other VTL nodes in the plurality of VTL nodes. ### Claim 5 (depends on 2) The system of claim 2, wherein the VTL node owns a least amount of scratch erased volumes relative to other VTL nodes in the plurality of VTL nodes. ### Claim 6 (depends on 1) The system of claim 1, wherein each processor is further configured to: determine a frequency at which the host requests use of scratch erased volumes in each of the plurality of VTL nodes; determine a ratio of a number of scratch erased volumes owned by each VTL node with respect to the frequency; and provide the ownership to the VTL node based on the ratio. ### Claim 7 (depends on 6) The system of claim 6, wherein the VTL node owns a least amount of scratch erased volumes with respect to the ratio. ### Claim 8 A method for managing a virtual tape library (VTL) domain coupled to a host, the VTL domain comprising a plurality of VTL nodes, each VTL node comprising a processor and configured to store a plurality of scratch erased volumes, the method comprising: receiving, by a first processor, a request from the host to de-mount a volume in one of the plurality of VTL nodes; transferring the volume to a scratch category in response to receiving the request; erasing data stored in the volume and categorizing the volume as a scratch erased volume; and providing ownership of the scratch erased volume to a VTL node in the plurality of VTL nodes based on pre-determined criteria for the plurality of VTL nodes. ### Claim 9 (depends on 8) The method of claim 8, wherein providing ownership of the volume comprises: comparing a number of scratch erased volumes owned by each VTL node with a predetermined threshold number of scratch erased volumes; and providing the ownership to the VTL node based on the comparison. ### Claim 10 (depends on 9) The method of claim 9, wherein the VTL node owns less than the predetermined threshold number of scratch erased volumes. ### Claim 11 (depends on 10) The method of claim 10, wherein the VTL node owns a least amount of scratch erased volumes relative to other VTL nodes in the plurality of VTL nodes. ### Claim 12 (depends on 9) The method of claim 9, wherein the VTL node owns a least amount of scratch erased volumes relative to other VTL nodes in the plurality of VTL nodes. ### Claim 13 (depends on 8) The method of claim 8, wherein providing ownership of the volume comprises: determining, by each respective processor, a frequency at which the host requests use of scratch erased volumes in its VTL node; determining, by each respective processor, a ratio of a number of scratch erased volumes owned by its VTL node with respect to the frequency; and providing the ownership to the VTL node based on the ratio. ### Claim 14 (depends on 13) The method of claim 13, wherein the VTL node owns a least amount of scratch erased volumes with respect to the ratio. ### Claim 15 A physical computer storage medium comprising a computer program product method for managing a virtual tape library (VTL) domain coupled to a host, the VTL domain comprising a plurality of VTL nodes, each VTL node comprising a processor and configured to store a plurality of scratch erased volumes, the physical computer storage medium comprising: computer code for receiving a request from the host to de-mount a volume in one of the plurality of VTL nodes; computer code for transferring the volume to a scratch category in response to receiving the request; computer code for erasing data stored in the volume and categorizing the volume as a scratch erased volume; and computer code for providing ownership of the scratch erased volume to a VTL node in the plurality of VTL nodes based on pre-determined criteria for the plurality of VTL nodes. ### Claim 16 (depends on 15) The physical computer storage medium of claim 15, wherein the computer code for providing ownership of the volume comprises: computer code for comparing a number of scratch erased volumes owned by each VTL node with a predetermined threshold number of scratch erased volumes; and computer code for providing the ownership to the VTL node based on the comparison. ### Claim 17 (depends on 16) The physical computer storage medium of claim 16, wherein the VTL node owns less than the predetermined threshold number of scratch erased volumes. ### Claim 18 (depends on 16) The physical computer storage medium of claim 16, wherein the VTL node owns a least amount of scratch erased volumes relative to other VTL nodes in the plurality of VTL nodes. ### Claim 19 (depends on 15) The physical computer storage medium of claim 15, wherein the computer code for providing ownership of the volume comprises: computer code for determining a frequency at which the host requests use of scratch erased volumes in each of the plurality of VTL nodes; computer code for determining a ratio of a number of scratch erased volumes owned by each VTL node with respect to the frequency; and computer code for providing the ownership to the VTL node based on the ratio. ### Claim 20 (depends on 19) The physical computer storage medium of claim 19, wherein the VTL node owns a least amount of scratch erased volumes with respect to the ratio.