JES planning considerations

Things to consider as you plan for Network Print Facility use in your JES environment are:

Decide how many NPF FSS writers you will use. Because each FSA subtask processes output for JES logical printers in parallel, system storage constraints might affect the amount of printing and throughput possible. There might be benefits in specifying 1 FSS writer with multiple FSA subtasks instead of multiple FSS writers each with a single FSA subtask.
You can parallel process output in two ways:
1. Using a single writer with multiple logical printers
2. Defining multiple writers with one printer each
Writers with multiple printers can be more efficient than having multiple writers with one printer each, because each writer has its own address space. If, however, the printers are of different priority or have a large disparity in job length, one printer might develop a backlog, and in this situation, it might be best to use multiple writers. See the topics on calculating the number of FSA subtasks, defining and managing JES3 resources, and running a printer by using an output FSS in either thez/OS JES2 Initialization and Tuning Guide or the z/OS JES3 Initialization and Tuning Guide
Decide how you can most effectively use the JCL CLASS parameter. The NPF FSS writer uses the CLASS parameter to decide which job to print. JES supplies the NPF FSS writer with SYSOUT based on a set of installation-defined criteria. Therefore IBM® recommends you define your selection criteria as CLASS. Multiple writers can use the same class, or each writer can be assigned to a different class.
The NPF FSS writer uses fields in the job separator page area (IAZJSPA) such as DEST, CLASS, job name, and user ID in addition to extension areas. Ensure your own changes made to this DSECT (or changes made in JES2 exit 23 or JES3 exit 45, for example) are compatible with the Network Print Facility FSS writer.
Accommodate the Network Print Facility's use of an 8 alphanumeric character name for destination. If you specify something longer in the DEST parameter of the JCL, you need to truncate that name for Network Print Facility use.
Accommodate the Network Print Facility's effect on JESNEWS. See Customizing JESNEWS for more information.
Determine the best NPF run-time options for your print environment.
The setting of the SPIN option might affect the print processing or generation of JES separator pages. NPF will process output from JES on either a data set level (SPIN=DATASET) or a group level (SPIN=GROUP).

For JES, an output group is defined as "A set of a job's output data sets that share output characteristics, such as class, destination, and external writer." For example, a job's LOG, JCL, and job messages, although three separate JES data sets, can be considered one output group.

See Modifying the NPF FSS writer start procedure for more information.