(ZOS) Run-time environment: Best practices for maintaining the runtime environment

Use these guidelines to make sure that WebSphere Application Server for z/OS is customized and maintained correctly, to support the installation's application workload.

Checking these basic software and hardware requirements can help you avoid problems with the run-time environment.

• Check that we have the necessary prerequisite software up and running. Check that they have the proper authorizations and that the definitions are correct.
• Check for messages that signal potential problems. Look for warning and error messages in the following sources:
  • SYSLOG from other z/OS subsystems and products, such as TCP/IP (especially the DNS, if in use), RACF, and so on
  • WAS for z/OS error log
  • SYSPRINT of the WAS for z/OS
  • Component trace (CTRACE) output for the server

• Check the ports used by WAS. The ports used by WAS must not be reserved by any other z/OS component.
• Ensure that z/OS has enough DASD space for SVC dumps. We might have to adjust the amount of space, because it depends on the size of the applications, on the configured Java virtual machine (JVM) heap size, and on the number of servant regions that might be included in one dump, and so on. For an SVC dump of one controller and one servant, we can start with a minimum of 512, but might have to increase the MAXSPACE to 1024 or higher, given the factors listed .
• Check your general environment. Does the system have enough memory? Insufficient memory problems can show up as AUX shortages, abends, or exceptions from the WAS for z/OS run-time. Sometimes the heap size for Language Environment (LE) and for the Java virtual machine (JVM) needs to be increased. If we are using RRS and DB2, make sure the system has enough space for archive data sets.
• Make sure all prerequisite fixes have been installed; a quick check for a fix can save hours of debugging.

  For the most current information on fixes and service updates, see:

  • The Preventive Service Planning (PSP) buckets for both WAS for z/OS and JAVA subsets of the WAS for z/OS Upgrade. To obtain a copy of the most current versions of these PSP buckets, we can either contact the IBM Support Center, use S/390 SoftwareXcel or link to IBMLink.

  • The Support web page of the WAS for z/OS website, which contains a table of the latest authorized program analysis reports (APARs).

  With the latest service information, check the following:

  • Ensure that all prerequisite PTFs (fixes) have been applied to the system.

  • Verify that all PTFs were actually present in the executables that were used at the time of error. Often, SMP can indicate that a fix is present and installed on the system when, in reality, the executables that were used at the time of error did not contain the fix.

Choose and using diagnosis tools and controls on z/OS

Diagnose problems (using diagnosis tools)