A storage management application determines that a source virtual tape requires reclamation, identifies all block addresses for active data of a source virtual tape and sorts the block addresses in an ascending order, identifies a target virtual tape which has sufficient free capacity to store the active data of said source virtual tape and the last written block address on said target virtual tape, and sends a command to the VTL-system instructing it to perform reclamation including information about said source and said target virtual tape, the sorted list of block addresses denoting active data on the source virtual tape and the starting block address on the target virtual tape. The reclamation logic references the active data host blocks of said source volume to said target virtual tape starting at said starting block address by just updating the host block to disk block mapping table.