The SYS parameter sets the defaults for the system, while the SUBSYS parameter sets the parameters for the specified subsystem. In this case, the SYS parameter turns on most of the SMF record types, most of the exits (which are not active unless specifically turned on), and sets the reporting interval.
Important: If you specify a SUBSYS parameter, it overrides all the named parameters that it includes. For instance, the SUBSYS (STC, EXITS, etc.) entry in the example mentioned in the Define z/OS SMF Record Exits shows the system that for started tasks it should only call the IEFU29, IEFU83, IEFU84, IEFU85, IEFU86, IEFUJP, and IEFUSO exits and not the IEFACTRT, IEFUTL, or the IEFUSI exits that are also specified in the SYS parameters. The SUBSYS parameter does not specify a TYPE parameter, so all the SMF record types specified in the SYS parameter will be reported.
The SMF-defined subsystems are JES2, JES3, STC, ASCH, and TSO. Other valid subsystems include IBM-supplied (such as OMVS), vendor-supplied, and user-defined subsystems.
If they are specified as a SUBSYS and if an EXIT parameter is specified, then IEFU83, IEFU84, and IEFU85 or IEFU86 (if extended record types are required) must be specified in the EXIT list for Ironstream to collect all the specified SMF record types.
If you are using both the standard and extended exits, Ironstream will ensure that only a single copy of an SMF record is flattened and forwarded.