Control-M Monitor and JES Considerations

The Control‑M monitor uses JES services to receive information about the status of the jobs running in the system.

Control-M tracks all jobs in the JES queue, even though some may await execution due to a lack of system resources (initiators). To prevent this unnecessary overhead, the user may utilize the MAXACTIV parameter in the SELECT section of the CTMPARM member in the IOA PARM library to limit the number of the jobs that Control-M submits by taking into consideration the number of jobs that the Control-M monitor is currently tracking.

This decreases the number of jobs waiting for initiators in the JES input queue and improves the performance of Control-M. The recommended value for MAXACTIV is the number of initiators serving the jobs submitted to Control-M, or a slightly higher number.

JES performance may be affected by long queues of duplicate jobs in SPOOL. When experiencing performance degradation, issue the JES operator command $D DUPJOB to check the maximum length of such the queues. For further details and instructions, contact IBM support.

To improve JES performance in a MAS/SYSPLEX environment, set the SDSB parameter in the CTMPARM member of the IOA PARM library to Y (default).

Control-M uses two types of JES requests to read job output from SPOOL:

• PSO requests are used when SDSB is set to F. PSO is effected by JES time slicing logic controlled by the HOLD/DORMANCY JES MAS (Multi Access SPOOL) parameters. For more information, see JES2PARM Tuning Considerations.
• SDSB is used when SDSB is set to Y (or even to N). SDSB is not effected by the high overhead involved in JES slicing.