Use this best practice to schedule downtimes on CA7ONL.
In a scheduled outage, you can use CA WA CA 7 Edition easily for effective recovery. You can stop job/task scheduling and submission to quiesce the batch processing before system shutdown. You can use CA WA CA 7 Edition data to ensure that processing continues with less disruption of service.
In the initial preparation for the outage, determine whether key CA7ONL files can handle a possibly backed-up workload. Start with an estimate of when and how long the system is down, and forecast the workload for that time frame. In other words, if the system outage is estimated to be 4-6 hours, forecast that date/spanned time with the FJOB command. If you have set up your jobs with the DRCLASS designations, you can forecast only those jobs with an activated DRCLASS. Get a count of jobs forecasted adding the number of jobs that are historically already in the queue then.
CA WA CA 7 Edition makes it easy to stop and restart the batch processing in an orderly manner. Use the STOP,Q=ALL command to halt the automatic submission of jobs. Any jobs that are already submitted continue to process on the operating system and go through completion processing when finished, but no new work is submitted to JES. You can stop the schedule scan with an SSCAN,TIME=0 command.
Before shut down, issue an SSCAN command and note the NEXT SCAN PERIOD START TIME. This time is the time frame that would be used to bring jobs into the queue with a start time that would fall between that time and the calculated scan end time (discussed later) on its next job scan. This information is important when readying the system to resume normal processing.
Shut down CA7ONL. After a successful shutdown, run the log dump jobs against both log files (LOGP and LOGS) as 'insurance' for a seamless recovery.
When it is time to restart CA7ONL, the time noted on the SSCAN output (NEXT SCAN PERIOD START TIME) is important. If the date/time of the restart is before that time, start with the schedule scan and the queues active. If the date/time of the restart is after that time, steps are required to get back to the initial point of stoppage.
If the restart is past the noted NEXT SCAN PERIOD START TIME, start CA7ONL with the schedule scan deactivated and the queues stopped. (To deactivate the schedule scan at startup, use RUNOPT=NSTA on the INIT statement in the initialization file. And, to bring up CA WA CA 7 Edition with the queues stopped, use STOPQ=YES on the SCHEDULE statement in the initialization file.)
To resume job submission, enter a START,Q=ALL command. To resume the schedule scan automated facilities requires that you enter a series of commands. When CA7ONL is started with a cold type of start, schedule scan is set to current time. To restart schedule scan, set the NEXT SCAN PERIOD START TIME with an SSCAN,DATE=yyddd,PERSTART=hhmm command to set the NEXT SCAN PERIOD START TIME to the date/time noted in the SSCAN output from before the shutdown.
After the NEXT SCAN PERIOD START TIME has been set, issuing SSCAN,SCAN=SCH wakes schedule scan immediately and looks for jobs with a start time that falls between the NEXT SCAN PERIOD START TIME and a calculated scan end time. (The calculation for scan end time is current time (time schedule scan started) plus SPAN plus QDWELL.) If this time frame would bring in too many jobs, you can set the schedule scan to work with intervals by adding a PEREND keyword to the SSCAN command as follows:
SSCAN,DATE=yyddd,PERSTART=hhmm,PEREND=hhmm
The scan end time is then set to the value entered on PEREND.
After the begin and end time for the schedule scan is set, issue an SSCAN, SCAN=SCH command. This command wakes up schedule scan for one scan only (if set with the PEREND). Automatic wake-up is turned off until a scan is done without the PEREND parameter. When all goes well, resumes normal processing.
Note: Verify that the PERFORM option of 5 on the INIT statement in the initialization file is not used in these situations:
In other words, when rescanning an already scanned time frame, duplicate checking is done during the first scan that occurs. However, if rescanning occurs on any subsequent schedule scans, you can bring in duplicate work when using PERFORM=5 on the INIT statement in the initialization file.
Business Value:
Following these guidelines ensures that CA7ONL downtime is minimized.
Additional Considerations:
To recap:
Note the NEXT SCAN PERIOD START TIME from SSCAN output
S CA7ONL
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