WebSphere Application Server for z/OS propagates the performance context of work requests by using workload management (WLM) enclaves. Each transaction has its own enclave and is managed according to its service class.
The controller of a server, which workload management views as a queue manager, uses the enclave associated with a client request to manage the priority of the work. If the work has a high priority, workload management can direct the work to a high-priority servant in the server. If the work has a low priority, workload management can direct the work to a low-priority servant. The effect is to partition the work according to priority within the same server.
To communicate the performance context to workload management, you must classify the workloads in your system according to the following work qualifiers.
Work qualifier abbreviation | Work qualifier | Corresponding WebSphere Application Server for z/OS entity |
---|---|---|
CN | Collection name | Cluster name |
UI | User ID | User ID under which work is running |
For more information about classification rules and workload qualifiers, see z/OS MVS Planning: Workload Management and Classifying z/OS workload.
In addition to client workloads, you must consider the performance of the WebSphere Application Server for z/OS run-time servers and your business application servers. In general, server controllers act as work routers, so they must have high priority. Because workload management starts and stops servants dynamically, servants also need high priority to be initialized quickly. After the servants are initialized, they run work according to the priority of the client enclave, so the servant priority that you assign has no significance after initialization.
In summary, use the following table to set the performance goals for each class:
If you are classifying... | ... assign it to: | Explanation |
---|---|---|
Location service daemon | SYSSTC or a high velocity, high importance STC | The system treats it as a started task, and it must route work requests quickly. |
WebSphere Application Server controller | SYSSTC or a high velocity, high importance STC | A controller must route work quickly, but you must balance the priority of your business application server with other work in the system. |
WebSphere Application Server servant | A lower velocity and importance STC than the controller | The servant should be assigned a lower goal
than the controller because the servant is less important than the
controller. ![]() |
WebSphere Application Server application environment | Use the CB classification rules, the percentage response time goal, for example 80% of transactions complete in .25 seconds. | |
Client applications | Assuming a long-running application, a velocity goal should be used that is relative to other work on the system. |