Application server log files and trace files

WebSphere® Application Server in basic log mode writes the following log files:
SystemOut.log
This log file records information about the processing of the application server and the enterprise applications that run on it. The default size is 1 MB.
SystemErr.log
This log file records information about errors that occur during the processing of the application server and the enterprise applications that run on it. The default size is 1 MB.
native_stdout.log
This log file records information about the processing of the JVM, for example, the version and path information. There is no limit to the size of this log file.
native_stderr.log
This log file records information about errors that occur during the processing of the JVM. This log can be configured to also show information about garbage collection. There is no limit to the size of this log file.
trace.log
This log file is written only if tracing is enabled for the application server (see Tracing enterprise applications. The default size is 20 MB.
WebSphere Application Server in HPEL log mode writes the following log files:
logdata/*.wbl
Log entries about the processing of the application server and the enterprise applications that run on it. This file combines the entries from SystemOut.log and SystemErr.log of the basic log mode.
tracedata/*.wbl
Trace entries about the processing of the application server and the enterprise applications that run on it. This directory contains the additional entries from trace.log of the basic log mode. Entries that are written to the logdata/ directory are not duplicated here.
native_stdout.log
This log file records information about the processing of the JVM, for example, the version and path information.
native_stderr.log
This log file records information about errors that occur during the processing of the JVM. This log can be configured to also show information about garbage collection.
TextLog_<timestamp>.log
This log file records the log entries from the logdata/ and tracedata/ directories, formatted as text. It can be disabled altogether or restricted to contain only log data, but not trace data.
Each WebSphere Application Server stores its log files in a separate directory with a name of the form: 
<profile_dir>/logs/<server_name>/
For example, if the application server profile is in directory /usr/IBM/WebSphere/AppServer/profiles/AppSrv01, the log files for the application server with the name server1 are stored in the directory: 
/usr/IBM/WebSphere/AppServer/profiles/AppSrv01/logs/server1

If a SystemOut, SystemErr, or trace log file reaches its size limit, its contents are saved in a new file, called a history log file, and the log file is cleared. Each history log file is given a name that includes a time stamp. To configure the size limit of the log files, and the number of history log files that are kept, perform the following steps:

  1. Log in the administrator console as an application server administrator.
  2. Click Troubleshooting > Logs and Traces.
  3. Select the name of the server for which the log files are to be configured.
  4. To configure settings for SystemOut.log and SystemErr.log, click JVM logs.
  5. To configure settings for trace.log, click Diagnostic Trace.
  6. To configure settings for logdata/*.wbl, click Configure HPEL logging.
  7. To configure settings for tracedata/*.wbl, click Configure HPEL trace.
  8. To configure settings for TraceLog_<timestamp>.log, click Configure HPEL text log.