JCL and typical parameters for Acquire/DASD are supplied in two members in the issued JCL library as detailed below.
If you intend to run in Cyclic Mode you must ensure the ACQDMON program is link edited with AC(1) in the parameters and placed in an APF authorized library. ACQDMON needs to be authorized to be able to invoke some system routines that gather information, and also to be able to pass records into the SMF subsystem. The sample JCL link edits ACQDMON with AC(1), but this on its own does not make it an authorized program. It has to reside in an APF-authorized library for this. There is no problem running ACQDMON linked with AC(1) from a non-APF library when using Single Shot Mode as it will not attempt to use any system facility that requires this privilege.
When running in Cyclic Mode ACQDMON will continue to run until a z/OS stop command is issued for it (e.g., P ACQDMON). Due to an internal polling delay it may take several seconds or minutes before the stop command is acknowledged, but once it is, it should stop almost immediately.
When running in Single Shot Mode, ACQDMON will terminate when all DCOLLECT data has been processed.
The amount of information captured about each disk volume, storage group or dataset group is quite small, so to avoid myriad SMF records being created at each capture interval Acquire/DASD will pack up to 400 items of a particular type into a single SMF record. Subtypes are used to differentiate data for Acquire.
If you have a system with 2,630 disks and 40 storage groups, and have defined 20 dataset groups, in each interval for which data is captured, you will generate :
7 records of volume data (subtype 1) - 6 with 400 disks in each, and 1 with the remaining 230
1 record of storage group data (subtype 2)
1 record of dataset group data (subtype 3)