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.

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Where to find more information This information references the following publications for further details about initializaion topics. You can use the following tools for analysis of performance-related data. However, in some cases, if the checkpoint is held long enough, the process can be done in one checkpoint cycle. There are no hard and fast recommendations to follow. This adjustment has instant effect and reflects real-time values jed2 opposed to an average over a stated period.

This facilitates concurrent read and write to track groups within the same data set extent. You should adopt tuningg or duplex mode. All commands that have the JES2 command prefix followed by a J are sent to the monitor command subtask.

JES2 restarts it automatically within a few minutes. So, why not make the HOLD value very small so that no member abd the checkpoint longer than necessary? This information could include technical inaccuracies or typographical errors. It should be noted that access to the spool is not wholly initiapization by the checkpoint.

The prime objective is initializatoin. This is particularly useful where a PSO application is in use and experiencing problems. You only need to serialize on the checkpoint if you modify the content of one of the queues. Many JES2 processes do not require checkpoint or require it very infrequently. You can then analyze the trace information that is in the dump. Placing the primary checkpoint on DASD while the secondary checkpoint resides on a coupling facility provides no benefit to an installation.

JES2 Performance and Availability Considerations 13 General anv tracking As your environment grows, you should understand how this growth affects initializayion limitations of key operating system components. The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law: Start high, and then lower it if there are problems and you do not see the messages when you wanted to.


For more information, refer to: 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. Processing time The processing time is the amount of time that it takes to perform the mechanical functions of passing the checkpoint among the members in the complex.

Complex useful time During a checkpoint cycle it is important to ensure that some member of the complex is using it. You should use this command on a regular basis. The checkpoint cycle time then refers to the total time it takes for each processor in jse2 complex to obtain ownership of the checkpoint, hold it, and then release control.

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IBM may not offer the products, services, or features discussed in this document in other countries. This data should be compared for all systems to establish which member has the most activity. You may copy, modify, and distribute these sample programs in any form without payment to IBM for the purposes of developing, using, marketing, or distributing application programs conforming to IBM’s application programming interfaces.

Identifying issues with JES2 performance degradation One of the reasons this study was done is because JES2 provides no internal performance monitor. These are specified in hundredths of a second.

Abstract for JES2 Initialization and Tuning Reference

Spool affinity is not controlled by a JES2 initialization statement. This isolation can prove beneficial for systems with a tendency to be output intensive, so protecting the other members of the MAS.

This information documents all JES2 initialization statements, in alphabetic order. This round-robin approach might break when the number of JES2 members increase. IBM may use or distribute any of the information you supply in any way it initiwlization appropriate without incurring any obligation to you. Also, it might be possible to have a unit of JES2 work become processor intensive and prevent the checkpoint processes from ending the hold period.


If output processing overhead is high, it could be because poor work selections are set. 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. This information references the following publications for further details about specific topics.

The limit on the number of job tunong elements JOEs is Many sysout files are never really printed, but are viewed and further processed directly from the spool space under TSO using a software product like SDSF. The Usermod will require a JES2 cold start.

Jobs queue and job output elements The current limits for these control blocks are: It facilitates the split of a large DASD spool pool into smaller pools for critical systems. In such cases, commands respond quickly, printers pick up work sooner, and so forth. Preliminary to that, we might want to know a little about the basic pieces involved. In duplex mode the 4 KB pages are changed.

If all members are significantly greater than what was set, then your goal might not be attainable. In this instance, WLM takes no action on the image in question.

z/OS JES2 Initialization and Tuning Guide

TSO logons are delayed. The 64 KB track size limit is in part due to the limits on allocating a data set extent. This information describes JES2 initialization statements and their parameters and provides summary charts that highlight details of the statements. However, refer to the following for specification of these values: You may copy, modify, and distribute these sample programs in any form without payment to IBM, for the purposes of developing, using, marketing or distributing application programs conforming to the application programming interface for the operating platform for which the sample programs are written.