Database Reference
In-Depth Information
Suite 11g Infrastructure
, we will discuss approaches in troubleshooting warning
or failed managed server states.
Monitoring the JVM
Although there are too many areas surrounding JVM monitoring to describe
here, three of the more important ones include ensuring that the heap allocated
to the JVM is appropriately sized (that is, comparing heap versus non-heap us-
age), that there is not excessive garbage collection, and JVM thread perform-
ance. Perform the following steps to monitor the key JVM statistics:
1.
Log in to the Oracle WebLogic Server Administration Console.
2.
On the home page, click on
Servers
.
3.
Navigate to the
Monitoring
|
Performance
tab.
4.
Here, the total heap size and the percentage of free heap are displayed.
5.
Click on the
Garbage Collect
button. Observe how much
Heap Free Cur-
rent
is freed before and after garbage collection.
Oracle WebLogic Server 11g also provides a dashboard that provides real-time
monitoring of many metrics, including the JVM runtime heap. This is helpful to
review while there is a heavy load on the system as it allows you to view the
current and free heap size.
Log in to the Oracle WebLogic Server Administration Console and click on
Mon-
itoring Dashboard
. Select
JVM Runtime Heap
and click on the start button.
The
Heap Size Current
and
Heap Free Current
are graphically displayed for
all running servers as shown in the following screenshot. If the free heap hov-
ers around zero for a considerable time, this is an indication that the heap size
may be configured too small. If repeated and frequent garbage collections oc-
cur without much memory being freed up, additional JVM monitoring may be re-
quired at that point.
