Mapping locations of logical volume records on a physical stacked volume

1. A virtual tape storage (VTS) system, comprising:

random access storage media;

sequential access storage media;

support for at least one virtual volume; and

a storage manager having:

logic adapted for determining a physical block ID (PBID) that corresponds to a starting logical block ID (SLBID);

logic adapted for building a mapping table for the at least one virtual volume, wherein the mapping table comprises a plurality of entries, wherein each entry includes a SLBID that corresponds to a PBID of a physical block stored to the sequential access storage media; and

logic adapted for copying a portion of a logical volume from the sequential access storage media to the random access storage media without copying the entire logical volume.

2. The system as recited in claim 1 , wherein a storage capacity of the sequential access storage media is at least 5 times greater than a storage capacity of the random access storage media.

3. The system as recited in claim 1 , further comprising logic adapted for compressing host data records prior to storing the host data records to the at least one virtual volume.

4. The system as recited in claim 1 , wherein a host system provides the VTS system with information that directs the VTS system to the portion of the logical volume to copy, wherein the information that directs the VTS system to the portion of the logical volume to copy includes a SLBID.

5. The system as recited in claim 1 , wherein the mapping table comprises an entry for each physical block stored to the sequential access storage media.

6. The system as recited in claim 1 , wherein the mapping table comprises an entry for every Nth physical block stored to the sequential access storage media, wherein N is a positive integer having a numerical value less than a total number of physical blocks stored to the sequential access storage media.

7. The system as recited in claim 1 , wherein the VTS system employs a hierarchical storage system.

8. The system as recited in claim 7 , wherein the random access storage media comprises magnetic disk media and the sequential access storage media comprises magnetic tape media.

9. The system as recited in claim 1 , further comprising logic adapted for providing access to the portion of the logical volume copied to the random access storage media.

10. The system as recited in claim 1 , further comprising logic adapted for receiving a mount request to access at least one host data record stored to the sequential access storage media.

11. The system as recited in claim 10 , wherein the portion of the logical volume is determined such that the at least one requested host data record is copied.

12. The system as recited in claim 10 , wherein the SLBID is provided in the mount request.

13. The system as recited in claim 12 , wherein the mount request further includes a block count value, wherein only a number of physical blocks corresponding to the block count are copied to the random access storage media.

14. The system as recited in claim 13 , wherein the mount request further includes a block size field.

15. The system as recited in claim 10 , wherein the SLBID is provided by an application sending the mount request.

16. The system as recited in claim 15 , further comprising receiving a block count value from the application, wherein only a number of physical blocks corresponding to the block count are copied to the random access storage media.