• WAS v8.5 > Troubleshoot > Troubleshoot applications with HPEL > HPEL

    Basic mode and HPEL mode

    Two modes of logging and tracing exist in the product, which are basic mode and HPEL mode. Use this topic to understand the differences between these modes.

    IBM recommends using the HPEL log and trace infrastructure. With HPEL, one views logs using the LogViewer command-line tool in PROFILE/bin.

    Basic mode, the default mode, is the existing log and trace framework from prior releases of WebSphere Application Server. Any existing scripts and tools we have that use logs and trace might need minor modifications to work with HPEL mode.

    To take advantage of the new log and trace framework, HPEL mode must be enabled. Once HPEL mode is enabled the JVM logs (typically SystemOut.log and SystemErr.log), the trace.log (typically trace.log), and the service log (typically activity.log) are no longer written to. Instead, log and trace content is written to a log data or trace data repository in a proprietary binary format and, if configured, to a text log file. Disabling the writing of the text log file results in the largest possible performance benefit of HPEL. A log viewing tool, LogViewer, is provided to allow for viewing, filtering, monitoring, and formatting the log and trace data in the repositories.

    The following figure shows the files used by the basic mode and HPEL mode log and trace facilities. When enabled, the HPEL text log file stores content from Java trace (optional), Java logs, System.out, and System.err. We can disable the HPEL text log in cases where it is not needed as indicated by the dotted lines.

    Figure 1. Log and trace files

    Basic mode and HPEL mode files. This table shows where each of the application and application server log, trace, JVM log, and native JVM log content is routed and how to view that content.

    Source Basic mode files HPEL mode files How to view the HPEL files
    System.out SystemOut.log

    trace.log (when trace enabled)

    		logdata/*.wbl

    TextLog_<timestamp>.log (when text log enabled)

    		logdata - use LogViewer, with optional filtering, to render log data repository as readable text, then use any text editor

    TextLog - any text editor

    System.err SystemErr.log Same as System.out Same as System.out
    java.util.logging (levels DETAIL and above) SystemOut.log

    activity.log

    trace.log (when trace enabled)

    		Same as System.out Same as System.out
    java.util.logging (levels below DETAIL) trace.log tracedata/*.wbl

    TextLog_<timestamp>.log (when text log enabled)

    		tracedata - use LogViewer, with optional filtering, to render trace data repository as readable text, then use any text editor

    TextLog - any text editor

    native cout native_stdout.log native_stdout.log Any text editor
    native cerr native_stderr.log native_stderr.log Any text editor

    The following table describes the MBean services:

    Basic mode and HPEL mode MBeans. This table shows the JMX MBeans associated with the basic mode and HPEL mode log and trace frameworks.

    Basic mode MBeans HPEL mode MBeans HPEL MBean Descriptions
    RasLoggingServiceMBean RasLoggingServiceMBean Provides JMX Notification

    		HPELLogDataServiceMBean Configures the log repository such as location, retention policy, out of space behavior, buffering, and file switching

    		HPELTraceDataServiceMBean Configures the trace repository such as location, retention policy, out of space behavior, buffering, and file switching

    		HPELTextLogServiceMBean Configures the text log such as location, retention policy, out of space behavior, buffering, file switching, and SystemErr or SystemOut format
    TraceServiceMBean HPELControlServiceMBean Configures trace specification levels, and provides access to log and trace repository content


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