关于WAS的Log和Diagnose

感觉WAS的Support主要就是分析Log和Dump文件，然后做出Diagnose，以下内容摘抄于：Summary of diagnostic information

Javadump

The Javadump is sometimes referred to as a Javacore or thread dump in some JVMs.

This dump is in a human-readable format produced by default when the JVM terminates unexpectedly because of

an operating system signal, an OutOfMemoryError exception, or when the user enters a reserved key combination(for example, Ctrl-Break on Windows).

You can also generate a Javadump by calling a method from the Dump API, for example com.ibm.jvm.Dump.JavaDump(), from inside the application.

A Javadump summarizes the state of the JVM at the instant the signal occurred.

Much of the content of the Javadump is specific to the IBM JVM.

See Using Javadump for details.

Heapdump

The JVM can generate a Heapdump at the request of the user(for example by calling com.ibm.jvm.Dump.HeapDump() from inside the application) or 

by default when the JVM ends because of an OutOfMemoryError exception.

You can specify finer control of the timing of a Heapdump with th -Xdump:heap option.

For example, you could request a Heapdump after a certain number of full garbage collections have occurred.

The default Heapdump format (phd files) is not human-readable and must be processed using available tools such as Memory Analyzer.

See Using Heapdump for more details.

System dumps

System dumps(also known as core dumps on Linux platforms) are paltform-specific files that contain information about the active processes, threads, and system memory.

System dumps are usually large.

By default, system dumps are produced by the JVM only 

when the JVM fails unexpectedly because of a GPF(general protection fault) or a major JVM or system error.

You can also request to system dump by using the Dump API.

For example, you can call the com.ibm.jvm.Dump.SystemDump() method from your application.

You can use the -Xdump:system option to produce system dumps when other events occur.

Garbage collection data

A JVM started with the -verbose:gc option produces output in XML format that can be used to analyze problems in the Garbage Collector itself or 

problems in the design of user applications.

Numerous other options affect the nature and amount of Garbage Collector diagnostic information produced.

See Garbage Collector diagnostic data for more information.

Trace data

The IBM JVM tracing allows execution points in the Java code and the internal JVM code to be logged.

The -Xtrace option allows the number and areas of trace points to be controlled, as well as the size and nature of the trace buffers maintained.

The internal trace buffers at a time of failure are also available in a system dump and tools are available to extract them from a system dump.

Generally, trace data is written to a file in an encoded format and then a trace formatter converts the data into a readable format.

However, if small amounts of trace are to be produced and performance is not an issue, trace can be routed to STDERR and will be pre-formatted.

For more information, see Tracing Java applications and the JVM.

Other data

Special options are available for producing diagnostic information relating to

• The JIT (see JIT and AOT problem determination)
• Class loading (see Class-loader diagnostic data)
• Shared classes (see Shared classes diagnostic data)

You can also download the IBM Monitoring and Diagnostic Tools, a set of freely-available GUI-based tools for monitoring applications and analyzing diagnostic data. For more information, see  IBM Monitoring and Diagnostic Tools .