Sequential Media Reclamation and Replication

Sequential media reclamation is usually performed after portions of a sequential access volume's data are no longer needed and the unused portion of the volume exceeds a threshold. Improved sequential media reclamation is provided by using a sequential access disk volume (for example, a volume of a virtual tape library (VTL)) embodied as a sparse file. Reclamation of objects stored in the volume is accomplished by nulling out regions of the sparse file that contain the objects that are no longer needed. A replication method is also provided in which information about the objects stored in the sparse file (such as offset and length) is used during replication to enable the correct portions of a target volume (embodied as a sparse file) to be nulled out to match a source volume (also embodied as a sparse file).