Logging and tracing

The Integrated Solutions Console provides a variety of logs to collect logging messages. System messages from the server are written to general-purpose logs such as the JVM logs and the IBM® service log.

Other logs are very specific in nature and focused on a component or activity. The general purpose logs such as the JVM logs and the IBM service log are helpful in monitoring the health of the application server, however, the problem determination procedure for a specific component might instruct you to examine the contents of a component- or product-specific log. This section describes the log files available for IBM WebSphere® Application Server, the logs that the server and services make use of, and how you can configure and view the files.

To begin troubleshooting a problem, check the JVM log files first. The JVM log files collect output for the System.out and System.err output streams for the application server process. One log file is specified for the SystemOut.log output stream and one file is specified for the SystemErr.log output stream. The SystemOut.log is most useful for monitoring the health of the running application server but it can also help in determining a problem, however, it is best to use the IBM Service log and the advanced capabilities of the Log Analyzer to determine a problem. The SystemErr.log contains exception stack trace information that is useful when performing problem analysis. For more information on general purpose logs see Diagnosing problems with message logs.

For runtime code problems, examine the general-purpose logs first. If that is insufficient, set a diagnostic trace. For more information about logging and tracing, go to the Monitoring and Troubleshooting documentation for distributed operating systems in the WebSphere Application Server Library at WebSphere Application Server Library

The log and trace files are self-managing to the extent that they can be configured not to grow beyond a certain size. Also, you can set the number of historical, or archived, files to keep and designate which of the log files to rollover or archive based on time or size or both. For more information on Setting log files size and rotation see Setting log file size and rotation.

For more information about logging and tracing, go to the Monitoring and Troubleshooting documentation for distributed operating systems in the WebSphere Application Server Library at http://www-01.ibm.com/software/webservers/appserv/was/library/.