Troubleshooting using WebSphere variables

Troubleshooting problems can be performed by changing certain variables in the application environment.

WebSphere Application Server for z/OS provides configuration variables that control server behavior.

• Configuration variables may be set on a cell, node, or server level.

  • Variable values set on a cell level apply to all servers in all nodes in the cell, unless a different value for the same variable is set on a node or server level. Variable settings on a node or server level override values for the same variable set at the cell level.

  • Variables set on a node level apply to all servers in the node, unless a different value for the same variable is set on the server level. Variable settings on a server level override values for the same variable set at the node or cell level.

  • Variables set on a server level apply only to the specific server, not to any other servers in the same node or cell.

  When you are diagnosing particular problems, you are most likely to alter variable values on a server level, for a particular server. Specifying variable values on the server level affects both the controller and servant regions.

• You may use scripting interfaces, instead of the administrative console, to alter configuration variable values.

• These variables allow you to control:

  • Output destinations and characteristics for the error log, and for CTRACE buffers, data sets and the external writer.

  • Trace buffers, data sets, and the content of trace data.

  • Types of dumps to be requested.

  • Timeout values for system and application behavior.

Depending on the types of problems you encounter, we might need to change the values set for configuration variables that control WebSphere Application Server behavior. Generally speaking, the default values are designed for normal operation in a production environment. Other circumstances might require different values:

• When you first customize and verify WebSphere Application Server for z/OS installation, or

• When you test application workloads in a test environment, or

• when you encounter a problem, and need to collect more diagnostic data.

The following procedure explains how to use the administrative console to change configuration variable values, commonly known as console settings.

1. Click Environment -> Manage WebSphere Variables in the console navigation tree.

2. On the WebSphere Variables page, select Server as the scope of the variable setting, and click Apply.

3. On the WebSphere Variables page, click New.

4. On the Variable page, specify a name and value for the variable. So other people can understand what the variable is used for, also specify a description for the variable. Then click OK.

5. Verify that the variable is shown in the list of variables.

6. Save the configuration.

7. To have the configuration take effect, stop the server and then start the server again.

Subtopics

• Types of configuration variables
  We can configure a variety of configuration variables to control the behavior of WAS for z/OS.

• 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.

• System controls: Best practices for using system controls
  Use this information as the best way to configure system controls.

• Performance diagnosis information
  The following report options are listed here for information. IBM Service may request that you run one or more of these reports while assisting you with diagnosis. You do not need to collect this data unless it is requested by IBM Service.

• Update the CFRM policy
  We must update the coupling facility resource management (CFRM) policy before using log streams that are CF-resident, such as the WAS error log and RRS logs. If we have the source for the current active CFRM policy, update the source and use the IXCMIAPU Administrative Data utility to generate the new policy.

• Error Dump and Cleanup interface
  The Error Dump and Cleanup (BBORLEXT) interface exists to call WebSphere Application Server for z/OS in a recovery environment to allow it to request a dump and to clean up its resources.

• Displaying information about current application server work
  We can use either the administrative console or z/OS MVS™ console commands to accomplish multiple operator tasks related to application servers. The z/OS display or modify console commands can be used to obtain information about the work an application server is performing. We can also use these commands to perform tasks that are useful in diagnosing application server problems.