You want to capture WebLogic internal events correlated with JVM events for viewing offline. What
three actions must you take to enable this within WebLogic?
A.
Run WebLogic in a JRockit JVM and ensure the Flight Recorder is enabled.
B.
Configure the WebLogic Diagnostic Framework Event Volume to Low, Medium, or High
depending on the type of events you want to capture.
C.
Configure the WebLogic Diagnostic Framework bridge to send events to the JRockit Flight
Recording.
D.
Take a dump from the default recording or create a new recording for the time period you want
to capture.
Explanation:
A: You can enable JFR at runtime to take JRA recordings from the JRockit
Management Console. You also have the option of turning off the JFR and recordings at the
JRockit JVM level from the java command line using:
$ java -XX:-FlightRecorder
B:
* In most environments, there is little performance impact when the Diagnostic Volume is set to
Low and the most performance impact if Diagnostic Volume is set to High. The volume of
diagnostic data produced by WebLogic Server needs to be weighed against potential performance
loss.
* WLDF provides the Diagnostic Volume attribute to set the amount of code coverage that is
enabled and the amount of data provided in the events that are generated for the covered code
The following code example sets the volume to Medium:
connect()
edit()
startEdit()
cd(“Servers/myserver”)
cd(“ServerDiagnosticConfig”)
cd(“myserver”)
cmo.setWLDFDiagnosticVolume(“Medium”)
save()
activate()
D: Integrated with the WebLogic Diagnostic Image and Watch and Notification
system
• Enables capture based on system state, event – capture during event; no need to replicate
• Watch for stuck thread count, heap size increase, available memory, etc.
• Set up notifications: capture WLDF image
• Diagnostic image capture spurs JFR file generation; JFR file included in diagnostic image
• Includes full JFR data from all event generatorsNote:
* WebLogic Diagnostic Framework (WLDF) provides specific integration points with JRockit
Mission Control Flight Recorder. WebLogic Server events are propagated to the Flight Recorder
for inclusion in a common data set for runtime or post-incident analysis.
Reference: Oracle Fusion Middleware Performance and Tuning for Oracle WebLogic Server,
Tuning WebLogic Diagnostic Framework and JRockit Flight Recorder Integration
Reference: JRockit Flight Recorder & WebLogic Diagnostic FrameWork (WLDF) Integration