DFSMSdss relocates data set extents on a DASD volume to reduce or eliminate free-space fragmentation, and reports about free space and other volume statistics. DFSMSdss allows you to perform the following tasks:

• Find the free space and volume statistics without defragmenting a volume.
• Specify that a volume be defragmented only if the space that is wasted by fragmentation exceeds a specified threshold.
• Use filtering to exclude selected data sets from defragmentation.