A method include forming an initial bitmap from the de-duplicated data on virtual volumes, sorting discrete blocks according to frequency of occurrence to form a revised bitmap to first include a plurality of most common discrete blocks, creating a physical volume map from the revised bitmap, reviewing, from the physical volume map, an initial virtual volume of the virtual volumes contained on a corresponding original physical volume, to determine whether moving the initial virtual volume to a different physical volume reduces the total number of data blocks in the physical volume map, deleting the initial virtual volume from its corresponding original physical volume and adding the initial virtual volume to the different original physical volume to create a revised physical volume map including revised physical volumes, and writing the revised physical volumes to the target set of physical media using the revised physical volume map.