You need to determine the system names and system group names that you want to specify in the SCDS. These systems and system groups constitute the SMS complex.

Before defining the base configuration, consider what you want to do with system-managed data sets that do not have a management class. You can specify a default management class for these data sets in the base configuration. You can create the management class any time before validating the SCDS. Defining the management classes is described in Defining management classes.

If the management class ACS routine does not determine a management class for a data set, DFSMShsm processes the data set using the default management class, if one exists. If you do not specify a default management class in your base configuration, DFSMShsm uses its own defaults.

If the management class ACS routine does not determine a management class for an object, the OSREQ request fails. This request can be OSREQ STORE, CHANGE, or OSMC class transition processing.

See z/OS DFSMS Implementing System-Managed Storage for additional planning information.