Abstract for JES2 Initialization and Tuning Guide · How to send your comments to IBM · Summary How to initialize JES2 in a multi-access SPOOL configuration. JES2 Initialization and Tuning Guide. z/OS JES2 Initialization and Tuning Guide contains the following information in support of JES2 Email Delivery Services. JES2 initialization statement and parameter summary tables · JES2 initialization statement descriptions · APPL(jxxxxxxx) – Application Characteristics.
Consequently, this should be performed at a quiet time. Placing a checkpoint on a coupling facility structure ensures equal access among MAS members and provides a better use of system resources than those available through DASD. You can store the data initiallzation spreadsheet format and portray it graphically to emphasize growth. In some cases similar considerations can apply for the use of SYSOUT print classes and the routing of such output to go to particular printers or to be printed at jfs2 times.
We do not recommend placing both checkpoints on coupling facility initializatio or placing the primary checkpoint on DASD and the secondary checkpoint on a coupling facility structure. Ask around about the local rules and expectations.
A general recommendation is to work towards a cycle time of around two seconds. All health monitor commands have the JES2 command prefix, followed by a letter J. This information contains examples of data and reports used in daily business operations.
Classes are set up by your site, for your site. Rather than always writing to spool, it simply writes to storage initialixation and takes a dump when the JES2 performance issue is encountered.
IBM z/OS JES2 Initialization and Tuning Reference (SA)
Table 2 provides a list of the JES2 resources and the corresponding initialization statements that you can adjust. There are initializztion physical devices few card readers, but many variations of printers and vaguely printer-like devices. Just because one member is unable to access the queues another member might be performing useful work. All of these guning are fictitious and any similarity to the names and addresses used by an actual business enterprise is entirely coincidental.
From the perspective of a single member in a complex, checkpoint-related useful time is the time in a inifialization cycle, which starts at the beginning of the primary write and ends at the beginning of the final write. This paper discusses JES2 processor utilization, checkpoint and spool considerations, workload manager WLM managed initiators, scalability, command processing, and identifying issues with performance degradation.
This value reflects the number of jes22 accesses in that interval. Because only two bytes are allocated for the track portion of the address, no spool data set can cross the 64 KB track boundary guife a volume. Any references in this information to non-IBM Web sites are provided for convenience only and do not in any manner serve as an endorsement of those Web sites.
Besides simply queueing the input and output, the spooling subsystem schedules it. As a consequence, the use of PAVs and MA will significantly benefit your spool performance and should be exploited.
At this point, the suggested way is to switch more to a contention mode approach. This data provides high and low use thresholds of the requested resources. This type of checkpoint control has the advantage of ensuring that a member is always requesting the checkpoint. Documents Flashcards Grammar guied.
IBM z/OS MVS mainframe overview of JES2
Example 2 uses the output from Example 1. Spool affinity is not controlled by a JES2 initialization statement. However, even in inihialization circumstances, the impact is minimal. With the availability of jobs and output elements, these commands can take a significant amount of time to complete and have an overhead to performance.
The idea for this post came from a suggestion by Ian Watson.
This facilitates concurrent read and write to track groups within the same data set extent. However, there is no way to know for sure the details of how classes are set up at your particular site unless you ask about it. WLM attempts to distribute the initiators across all members in the sysplex to balance the use of the systems while taking care that jobs with affinities to specific systems are not hurt by WLM decisions.
Tuning the checkpoint really starts with getting a tunnig HOLD value for each system. On the other hand, with a shorter cycle time, JES2 appears to be much faster. Placing the primary checkpoint on DASD while the secondary checkpoint resides on a coupling facility provides no benefit to an installation. Processing time The processing time is the amount of time initializatikn it takes to perform the mechanical functions of passing the checkpoint among the members in the complex.
IBM has not tested those products and cannot confirm the accuracy of performance, compatibility or any other claims related to non-IBM products. All commands that have the JES2 command prefix followed by a J are sent to the monitor command subtask.
Every tenth intermediate write is also written to the down-level DASD data set. After JES2 reads a job into the system, JES2 writes the job, its job control language, its control statements, and its data to a spool data set until further processing can occur.
The 64 KB track size limit is in part due to the limits on allocating a data tunung extent. JES2 uses more processor cycles. The checkpoint locking mechanism is used to serialize access when any change is required to the JOB or OUTPUT processes that changes the content of the queues for example, a change in phase or processing status.
New initiators are started in circumstances such as the following: Other reasons could be error recovery dump processing or some other type of failure. So, why not make the HOLD value very small so that no member keeps the checkpoint longer than necessary? There are potential failure scenarios at UCB level that continue to qualify the availability benefits of fenced volumes.
If one particular PCE is shown to be far busier than others, then you can balance the associated work across more members of the MAS to spread out the activity. JES2 attempts to maximize the performance of spooling operations, which ultimately benefits the throughput of work through the JES2 installation.