Workload management can dynamically manage the number of batch
initiator address spaces in a JES2 or JES3 environment. You can selectively
turn over control of the batch initiator management to WLM for one
or more job classes. WLM will start new initiators, as needed, to
meet the performance goals of this work.
By specifying or defaulting MODE=JES on the JES2
JOBCLASS statement or the JES3 GROUP statement, you indicate that
the initiators for the job class should be JES-managed, as in the
past. By specifying MODE=JES, you keep the job class
in JES-managed mode. (JES will manage the batch initiators for that
job class, in the same way it has in prior releases.) By specifying MODE=WLM,
you put that class into WLM-managed mode.
You can switch as many job classes to WLM-managed mode as you wish.
You can easily switch any job class back to JES-managed mode by using
the JES2
$TJOBCLASS command or the JES3
MODIFY command.
Note: - If you have velocity performance goals set for the work running
on WLM-managed batch initiators, be aware that the initiation delays
will be figured into the velocity formula. This will affect your velocity
values and probably require some adjustment to your goals. See Defining service classes and performance goals for information on defining velocity
goals.
- All jobs with the same service class should be managed by the
same type of initiation. For example, if jobs in job classes A and
B are classified to the HOTBATCH service class, and JOBCLASS(A) is MODE=WLM,
while JOBCLASS(B) is MODE=JES, workload management
will have a very difficult time managing the goals of the HOTBATCH
service class without managing class B jobs.
- You can use the JES2 JOBCLASS parameter to specify
a default scheduling environment, thereby saving the effort of changing
JCL jobcards or writing a specific JES2 exit to assign the scheduling
environment.
- If a WLM initiator is experiencing ABEND822s, there
are two ways to recycle the initiator:
- If you can determine the ASID of the initiator that is abending,
you can stop it by issuing the P INIT,A=asid command.
The initiator does not need to be idle at the time that you enter
the command. If the initiator is busy processing a job, it will stop
itself after the job finishes. WLM will automatically replace the
initiator with a new one.
- If you cannot determine the ASID, or if you want to recycle all
initiators as part of a regular cleanup process, you can enter the $P
XEQ and $S XEQ commands. The $P
XEQ command causes all WLM initiators on that system to
be “flagged” to terminate. The $S XEQ command
enables WLM to start new initiators (without needing to wait for the
old initiators to end). Beware that the $P XEQ command
purges WLM's history which tells it how many initiators are needed
for each service class. It may take some time for WLM to build up
the same number of initiators that existed before.
See the following JES2 and JES3 documentation for more information
about WLM-managed JES2 job classes:
The following other functions exist to help you manage batch work
in a JES environment:
- A new work qualifier, PRI, which allows you
to use the job priority when defining work classification rules. See Defining classification rules.
- Scheduling environments, which allow you to define resource requirements
for incoming work, ensuring that the work will be scheduled on a system
within the sysplex only if the resource settings on that system satisfy
those requirements. See Defining scheduling environments.