Determining z/OS workload management importance

For full information about workload management and defining goals through the service definition, see z/OS MVS Planning: Workload Management.

This topic suggests how to set the z/OS® workload management importance and velocity goals relative to other important work in your system.

The queue manager address space needs to be defined with high priority as it provides subsystem services. The channel initiator is an application address space, but is usually given a high priority to ensure that messages being sent to a remote queue manager are not delayed. Advanced Message Security (AMS) also provides subsystem services and needs to be defined with high priority.

Use the following service classes:

The default SYSSTC service class

VTAM and TCP/IP address spaces
IRLM address space (IRLMPROC)

Note: The VTAM, TCP/IP, and IRLM address spaces must have a higher dispatching priority than all the DBMS address spaces, their attached address spaces, and their subordinate address spaces. Do not allow workload management to reduce the priority of VTAM, TCP/IP, or IRLM to (or below) that of the other DBMS address spaces

A high velocity goal and importance of 1 for a service class with a name that you define, such as PRODREGN, for the following:

IBM® MQ queue manager, channel initiator and AMS address spaces
Db2® (all address spaces, except for the Db2-established stored procedures address space)
CICS® (all region types)
IMS (all region types except BMPs)

A high velocity goal is good for ensuring that startups and restarts are performed as quickly as possible for all these address spaces.

The velocity goals for CICS and IMS regions are only important during startup or restart. After transactions begin running, workload management ignores the CICS or IMS velocity goals and assigns priorities based on the response time goals of the transactions that are running in the regions. These transaction goals should reflect the relative priority of the business applications they implement. They might typically have an importance value of 2. Any batch applications using IBM MQ should similarly have velocity goals and importance reflecting the relative priority of the business applications they implement. Typically the importance and velocity goals will be less than those for PRODREGN.