DFSMShsm processes system-managed DASD volumes in SMS pool storage groups. A pool storage group is a set of volumes with free space threshold and paths to the systems within the complex. Requests of data sets that have common storage requirements can more easily be satisfied by placing volumes in a storage group.

In a multiple-processing-unit environment, storage groups can be defined to allow DFSMShsm automatic functions to be performed for specific storage groups by specific processing units. This is in contrast to allowing storage groups to be processed by all processing units in a multiple-processing-unit environment.

DFSMShsm processes SMS pool storage groups at the copy pool level. A copy pool is a named set of storage groups. DFSMShsm processes these storage groups collectively by using the fast replication function. You can maintain as many as 85 backup versions for each copy pool. DFSMShsm can recover all of the volumes in a copy pool or an individual volume.

DFSMShsm continues to support volume pools that are not managed by the Storage Management Subsystem. Volume pools depend on the volume from which the data set last migrated. If the volume from which the data set last migrated is a member of a pool, DFSMShsm recalls the data set to any online volume in the pool. If the volume from which the data set migrated is not a member of a pool, DFSMShsm uses its nonpooling algorithms for recalling the data set.

Volume pooling allows the inclusion of individual applications or group volumes under DFSMShsm control. It provides the capability to manage independent pools of volumes according to specific, installation defined requirements. Volume pooling also allows the gradual placement of more volumes into a larger pool, thus benefitting from the increased performance, improved DASD space utilization, and additional flexibility of the larger resource. This gives the installation the opportunity to reevaluate its current pooling structures for possible consolidation, while still taking advantage of the automated space management features of DFSMShsm.