WebSphere® Application Server traces can
be extremely helpful in detecting and diagnosing problems.
By properly setting trace options, you can capture the information
needed to detect problems without significant performance overhead.
- Ensure that you are not collecting more diagnostic data than you
need.
You should check your WebSphere for z/OS® tracing
options to ensure that ras_trace_defaultTracingLevel=0 or 1, and that ras_trace_basic and ras_trace_detail are not set.
How to view or set: Use the WebSphere administrative console:
- Click Environment > Manage WebSphere Variables.
- On the Configuration Tab check for any of these variables in the
name field and observe the variable setting in the value field.
- To change or set a variable, specify the variable in the name
field and specify the setting in the value field. You can also describe
the setting in the description field on this tab.
- For the best performance with any level of tracing, including ras_trace_defaultTracingLevel=1, set ras_trace_outputLocation to BUFFER. This trace setting stores the trace data in memory,
which is later asynchronously written to a CTRACE data set. Setting ras_trace_outputLocation to SYSPRINT or TRCFILE provides
approximately the same level of performance, but significantly less
than BUFFER.
- You can use the ras_trace_BufferCount and ras_trace_BufferSize settings to control the amount of
storage used for trace buffers. Generally, the larger the buffer allocation,
the better the performance. However, specifying a buffer allocation
that is too large can cause a decrease in performance due to system
paging.
The default settings of ras_trace_BufferCount=4 and ras_trace_BufferSize=1M should perform
sufficiently for most applications.
- Make sure you disable JRAS tracing.
To do this, look for the
following lines in the trace.dat file pointed to by the JVM properties
file:
com.ibm.ejs.*=all=disable
com.ibm.ws390.orb=all=disable
Ensure that both lines are set to
=disable or delete
the two lines altogether.
Note: If ras_trace_outputLocation is set, you may be tracing and not know it.