The following are general recommendations you should follow when defining service classes.

• Service classes should not include jobs in JES-managed and WLM-managed job class group. Doing so weakens the relationship between the number of WLM-managed initiators and the queue delay that is observed. For example, if a velocity goal is used, queue delay is included in the velocity calculations for WLM-managed initiators. If a service class contains jobs in JES-managed and WLM-managed job class groups, queue delay will be included in the velocity calculations for some jobs but not all of the jobs in the service class.
• Service classes should be unique across a JESPLEX. If you run multiple JESPLEXs within a SYSPLEX, keep in mind that WLM policies are SYSPLEX-wide and WLM manages the performance goals for a service class at a SYSPLEX level (for example, performance goals based on the SYSPLEX performance index). If a service class is shared between two JESPLEXs, it is possible for a service class to be meeting its goals from a SYSPLEX, but not meeting its goals in a particular JESPLEX within a SYSPLEX.
• If class limits are specified on the Class initialization statement, jobs in that class should map to a single service class. If jobs in the class map to multiple service classes, more initiators may be started than necessary because each service class will be treated independently with respect to the class limits. When JES3 reports to WLM the number of eligible jobs in the service class, it will apply the class limits to each service class individually.