Programming Interface Information

In an SMS-managed environment, you generally allow the system to place data sets for you. If for some reason you want to control the placement of the data sets (for example, because of performance problems or because you want to put data sets on some new, empty volumes you have just added to a storage group), you must take special steps.

If you use OUTDDNAME or OUTDYNAM to specify a volume list, the volume serial numbers are passed as input to the ACS routines. Depending on how your ACS routines are written, this input might or might not be used in determining where to place the data set.

One way to guarantee that data sets go to particular volumes is to write your storage group ACS routine such that data sets are moved to the volumes you select.

Alternatively, if a data set’s storage class has the guaranteed-space attribute, the data set is placed on the user-specified volumes if the volumes reside in the same storage group and ACS selects that storage group for the data set. By using BYPASSACS and STORCLAS keywords, you can ensure that the storage group selected contains the volumes you specify with OUTDDNAME or OUTDYNAM. However, for this procedure to work, your storage group ACS routine must use storage class to determine the storage group for a data set. This allows you to determine which storage class to specify with the STORCLAS keyword to ensure that the storage group containing the volumes specified with OUTDDNAME or OUTDYNAM is selected.

End Programming Interface Information