1. A method for improving performance of a backup system comprising: performing a backup of a client device; tracking, using the client device, references to data segments that are located outside of a unit of storage associated with the backup, wherein the references are tracked by monitoring an amount of data associated with one or more generations of backups; calculating utilization of the unit of storage associated with the backup based on the tracked references; determining if the calculated utilization meets a specified parameter; and determining one or more responsive actions in the event the calculated utilization meets the specified parameter, wherein the responsive action comprises sending one or more segments of unchanged data of a unit of storage in a subsequent backup based on a determination that the calculated utilization of a unit of storage is below a specified threshold, wherein the one or more segments of unchanged data from a unit of storage are combined with segments of data from a second unit of storage into a new unit of storage to reduce data fragmentation for a backup.