Service definition
The service definition you set up contains all the information required by WLM to manage your workloads. The service definition consists of
Service policy
A service policy is a named set of performance goals used by WLM.
Different policies can be set up for different system requirements, but only one policy can be active for a particular sysplex at any one time. WLM uses the goals defined in the active service policy to schedule the appropriate resources for work in the sysplex.
Classification rules
Classification rules are the rules used to associate incoming work with a service class.
Resource group
A resource group is a service class or group of service classes that may be defined within a service policy.
By defining a resource group, you can assign the amount of processing capacity across one or more MVS images for those service classes within the resource group. Defining a resource group within a service policy is not required.
WORKLOAD (Service definition)
A workload is a group of service classes that are tracked and managed as a unit, usually because they have something in common.
Service class
A group of work that has the same performance goals, resource requirements, or business importance.
Up to 1000 service classes can be defined, and you can assign a performance goal for each service class.
Service class period
A service class period has a service goal and importance level assigned to a service class for a specific duration.
Generally, multiple periods are created for workloads that have changing resource requirements, such as TSO. As a service class consumes more resources than are defined for its duration, it moves to a different period within the service class. Each service class can have up to 8 periods defined.
Goals
You can assign a goal to each service class.
The assigned goals, along with the assigned importance value, help the WLM determine the distribution of resources. The four goal types are
- Average response time
- Percentage response time
- Execution velocity percentage
- Discretionary
A fifth type of goal, System, is assigned to workloads that need to receive the highest priority services.
Importance
Importance is the degree of importance of a service goal relative to other service class goals. The values for importance are:
1 | Highest |
|---|---|
2 | High |
3 | Medium |
4 | Low |
5 | Lowest |
In some instances, a goal may not have an importance value.
- For a Discretionary goal, work is run using any system resources not required to meet the goals of other work.
- For a System goal, work is run for all address spaces requiring high priority service.
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