Diagnose problems with message logs
JVM logs
The JVM logs are created by redirecting the System.out and System.err streams of the JVM to independent log files. WAS writes formatted messages to the System.out stream. In addition, applications and other code can write to these streams using the print() and println() methods defined by the streams. Some Developer Kit built-ins such as the printStackTrace() method on the Throwable class can also write to these streams.
Typically, the System.out log is used to monitor the health of the running appserver. The System.out log can be used for problem determination, but it is recommended to use the IBM Service log and the advanced capabilities of the Log and Trace Analyzer instead. The System.err log contains exception stack trace information that is useful when performing problem analysis.
Because each appserver represents a JVM, there is one set of JVM logs for each appserver and all of its applications located by default in the following directory:
- install_root/profiles/profile/logs/server
In the case of a WAS ND configuration, JVM logs are also created for the deployment manager and each node agent because they also represent JVMs.
Process logs
The process logs are created by redirecting the STDOUT and STDERR streams of the process to independent log files. Native code, including the JVM itself, writes to these files. As a general rule, WAS does not write to these files. However, these logs can contain information relating to problems in native code or diagnostic information written by the JVM.
As with JVM logs, there is a set of process logs for each appserver, since each JVM is an operating system process. For WAS ND configuration, a set of process logs is created for the deployment manager and each node agent.
IBM service log
The IBM service log contains both the WAS messages that are written to the System.out stream and some special messages that contain extended service information that is normally not of interest, but can be important when analyzing problems. There is one service log for all WAS JVMs on a node, including all appservers. The IBM Service log is maintained in a binary format and requires a special tool to view. This viewer, the Log and Trace Analyzer, provides additional diagnostic capabilities. In addition, the binary format provides capabilities that are utilized by IBM support organizations.
Other logs
In addition to these general purpose logs, WAS contains other specialized logs that are specific to a particular component or activity. For example, the HTTP server plug-in maintains a special log. Normally, these logs are not of interest, but you might be instructed to examine one or more of these logs while performing specific problem determination procedures.
View JVM logs
JVM log interpretation
Configure the JVM logs
Process logs
Configure the service log
View the service log