Managing space with DFSMSdss

DFSMSdss provides the following functions to help you manage DASD space:

COMPRESS: Compresses your partitioned data sets by taking unused space and consolidating it at the end of the data set. To make the unused space available for other data sets, you must use the RELEASE command. This does not apply to PDSEs.
CONSOLIDATE: Performs data set extent consolidation or reduction on a volume.
DEFRAG: Consolidates the free space on a volume to help prevent out-of-space abends on new allocations.
DUMP/RESTORE: Deletes unwanted data sets and combines data set extents. (You can also use the COPY command to combine data set extents.)
RELEASE: Releases the unused space in sequential, partitioned, and extended-format VSAM data sets for use by other data sets.

Related reading: For more information about managing space, see Managing space with DFSMSdss.