Methods and apparatuses for efficiently migrating deduplicated data are provided. In one example, a data management system includes a data storage volume, a memory including machine executable instructions, and a computer processor. The data storage volume includes data objects and free storage space. The computer processor executes the instructions to perform deduplication of the data objects and determine migration efficiency metrics for groups of the data objects. Determining the migration efficiency metrics includes determining, for each group, a relationship between the free storage space that will result if the group is migrated from the volume and the resources required to migrate the group from the volume.