Customization Best Practices › Implement Workload Balancing (WLB)

Implement Workload Balancing (WLB)

Use the Workload Balancing (WLB) feature that is designed to select the best mix of jobs to submit to the host system to meet defined objectives. WLB has numerous benefits including the class barriers (CA WA CA 7 Edition class, not JES), tape drive usage (if a CPU job), and the prioritized submission of jobs.

Start by defining what you want Workload Balancing to do. Do you want it to control tape drives? Do you want it to control the number of jobs submitted by class? Do you want it to control the submission of jobs by a user-defined priority? The System Programming Guide contains a table that discusses the steps for implementing Workload Balancing. Read this entire topic thoroughly to determine whether Workload Balancing can help you reach your job submission objectives. After you have set the goals, you are ready to do some preliminary tasks.

Answer the Workload Balancing Questionnaire (in the System Programming Guide). The answers to this questionnaire you establish and define your Workload Balancing goals. If you do not use Workload Balancing for tape drives or initiators, code the corresponding macros anyway. The TAPE1, TAPE2, and INITR macros have defaults that can stop the submission of jobs. For example: You want to use only the class barrier feature of Workload Balancing. Code the TAPE1 macro with the highest permitted value for 'total available.' If you do not code the TAPE1 macro, the total available tape drives default to zero, and jobs using a tape device are not submitted.

After you have coded the macros and assembled and link edited the Workload Balancing module, you have a load module named UCC7Rxxx. The xxx is the MODNAME value from the WLBPDEF macro. After adding the module as a job on the DB.1 panel (job name UCC7Rxxx), you can schedule this job the same as any job. Consider scheduling different Workload Balancing modules to be in effect at different times of the day or after certain processes complete. When the job UCC7Rxxx goes to the ready queue, the Workload Balancing module by that name is loaded and the UCC7Rxxx job flushes from the queues (like a nonexecutable job). (Obviously, UCC7R is a special job name prefix that can only be used for Workload Balancing modules.)

Once a Workload Balancing module is created, the values for that module can be viewed, modified, or both with online commands. The LWLB command lets you list the values for a specific Workload Balancing module. The XWLB command lets you modify the values of the current Workload Balancing module. A /WLB command can be issued using the Batch Terminal Interface, U7SVC, or the trailer step to modify the current Workload Balancing module from JCL or user-written programs. You can modify an individual job's Workload Balancing associated values in the following ways:

• Permanently on the DB.1 panel for number of tape drives used and CA WA CA 7 Edition job class.
• The XUPD command for a one-time change after the job is scheduled to run (currently in the queue).
• A #RES statement in the JCL of a job to change the resource values of the job.

Workload Balancing affects jobs waiting submission in the ready queue. Before you implement Workload Balancing, jobs usually remained in the ready queue only long enough to be submitted and initiated unless they were held by a virtual resource. After you turn on Workload Balancing, some jobs could stay in the ready queue longer. To determine the status of a job in the ready queue, look at the output from an LQ command. For jobs in the ready queue, a date and time in the column headed by SUB/START is the time that the job was submitted to JES. If *NONE* in this field, the job has not yet been submitted. To view the nonsubmittal reason, issue the following command:

LRDYP,JOB=jobname/job#,LIST=STATUS

Once the module is loaded and in effect, it can be too late to discover that you have not set all the options correctly. You can test your Workload Balancing modules with Workload Planning. Workload Planning is a modeling process that can test what-if scenarios. You can run Workload Planning with the default Workload Balancing module and then with the module you want to test to see how the new module affects processing.

Business Value:

This best practice helps ensure more efficient processing of batch work.

More Information:

For more information about Workload Balancing, see the Systems Programming Guide. For more information about Workload Planning, see the Report Reference Guide.