ACS environment considerations

Automatic Class Selection (ACS) environment considerations are applicable to the DATACLAS, MGMTCLAS, STORCLAS, and STORGRP selection criteria and the SET_DATACLAS, SET_MGMTCLAS, SET_STORCLAS, and SET_STORGRP functions.

SMS can make multiple calls to the ACS environment to determine the four SMS constructs of the data, storage and management classes and the storage group. For example, SMS might make an initial call to determine the data, storage and management classes and then make a second call to establish the storage group. When you use an SMS construct as a selection criterion, it is only considered a match if the particular selection criterion was requested in the call to the ACS environment.

For example, if ACS makes a call to determine the data class and a rule definition contains selection criteria for both data and storage classes, even if the data class matches the rule definition selection criterion, because a storage class selection criterion was specified, but the storage class was not requested in the ACS call, the rule definition is considered a non-match.

Note: SMS makes a single ACS call for all JCL-defined data sets before the start of the first step of the job. So, messages that are associated with changes to the Data Class, Storage Class, Management Class and Storage Group using the SET_DATACLAS, SET_STORCLAS, SET_MGMTCLAS, and SET_STORGRP Enhanced Allocation Management functions respectively, are displayed at the beginning of the job ahead of the execution of the first step.

Similarly, after a match is made on the selection criteria in a rule definition, the only SMS constructs that can be set with Advanced Allocation Management are the constructs that were originally requested in the call to the ACS environment. For example, if only the data class is requested in the call to the ACS environment, only the SET_DATACLAS Enhanced Allocation Management function is accepted. Specified SET_STORCLAS, SET_MGMTCLAS, or SET_STORGRP functions are ignored.