The z/OS Workload Manager
The z/OS® Workload Manager provides automatic and dynamic balancing of system resources (central processors and storage) across a sysplex.
- Adopting a goal-oriented approach
- Gathering real time data from the subsystems that reflect performance at an individual task level
- Monitoring z/OS- and subsystem-level delays and waits that contribute to overall task execution times
- Dynamically managing the resources of the sysplex, using the performance goals, and the real time performance and delay data, as inputs to system resource management algorithms.
This resource management is particularly significant in a sysplex environment, but is also of value to subsystems running in a single z/OS image.
- Improved performance through z/OS resource
management. Improvement can depend on many factors, for example:
- System hardware configuration
- How the system is partitioned
- Whether CICS subsystems are single or multiregion
- The spread of types of applications or tasks performed, and the diversity of their profile of operation
- The extent to which the sysplex workload changes dynamically.
- Improved efficiency of typical z/OS sysplexes through improved overall capacity and increased work throughput.
- Simplified z/OS tuning. Systems that have an operating signature that makes it difficult or time consuming to attain or maintain optimal tuning by current means can benefit the most.
The main benefit is that you do not need to continually monitor and tune CICS to achieve optimum performance. You can set your workload objectives in the service definition, then the workload component of z/OS manages the resources and the workload to achieve your objectives.
The z/OS Workload Manager produces performance reports that you can use to establish reasonable performance goals and for capacity planning.
The CICS function for z/OS workload management incurs negligible impact on CICS storage.
CICS support for the z/OS Workload Manager is initialized automatically during CICS startup. All CICS regions (and other z/OS subsystems) running on a z/OS image with z/OS workload management are subject to the effects of the Workload Manager.
User-written resource managers and other non-CICS code that is attached to CICS through the RMI should be modified to provide z/OS Workload Manager support, if workload management is to work correctly for CICS-based tasks which cross the RMI into such areas.
The IBM® Redbooks® Publication System Programmer's Guide to: Workload Manager, SG24-6472-03, gives a broad understanding of the Workload Manager component of the z/OS system. It covers basic aspects of WLM together with the new functions available in the z/OS release up to z/OS 1.7. The book provides a discussion on how to create WLM policies based on business goals and the types of transactions you run in your systems.