According to one embodiment, a computer program product includes a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising: computer readable program code configured to receive a mount request to access at least one host data record on a virtual tape storage (VTS) system; computer readable program code configured to determine a number of host compressed data records per physical block on a magnetic tape medium; computer readable program code configured to determine a physical block ID (PBID) that corresponds to the requested at least one host data record; computer readable program code configured to access a physical block on the magnetic tape medium corresponding to the PBID; and computer readable program code configured to output the physical block without outputting an entire logical volume from the magnetic tape medium that the physical block is stored to. Other systems and computer program products are also described.