Thanks a lot for your detailed reply. The JAVA_OPTS variable in $CATALINA_HOME/bin/startup.sh has the value as:
JAVA_OPTS="$JAVA_OPTS -Xms1303m -Xmx1303m -XX:MaxPermSize=256m -Dcwom.bl.ip=127.0.0.1 -Dcwom.bl.port=1399" I checked for free space on the VM instance with Red Hat Linux as the OS on which the Tomcat is hosted with a total memory of 19 GB, I found that there is around 8 GB of free space in the server. As per your inputs, I am planning to increase the memory allocation for Heap size and PermGen size to almost double as below: JAVA_OPTS="$JAVA_OPTS -Xms2048m -Xmx2048m -XX:MaxPermSize=512m -Dcwom.bl.ip=127.0.0.1 -Dcwom.bl.port=1399" I hope, this should avoid the hang-up issues where Tomcat does not seem to respond. I plan to implement this in the UAT environment at first and see how it goes. Regards -----Original Message----- From: Jeffrey Janner [mailto:jeffrey.jan...@polydyne.com] Sent: Monday, April 28, 2014 7:39 PM To: 'Randhir Singh' Subject: RE: How to monitor performance of tomcat > -----Original Message----- > From: Randhir Singh [mailto:randhir.si...@sterlite.com] > Sent: Monday, April 28, 2014 5:47 AM > To: Jeffrey Janner; Tomcat Users List > Subject: RE: How to monitor performance of tomcat > > Thanks for your valuable inputs. I am a bit of a novice to this. When > this problem happens, it is quite a loss of face in front of the users > who are widely spread geographically. I checked the catalina.out logs > on the 2 days that the problem happened on 23rd & 25th April, the > findings are as below: > > 23rd April '14: > > The catalina.out log showed the message like, > ---------------------------------------------------------------------- > - > ---------------------------------------------------------------------- > - > --------- > Caused by: org.jboss.remoting.InvocationFailureException: Socket timed > out. > Waited 300000 milliseconds for response while calling on > InvokerLocator [socket://<hostname of our > machine>:4173/?invokerDestructionDelay=5000&timeout=300000]; nested > exception is: > java.net.SocketTimeoutException: Read timed out > ---------------------------------------------------------------------- > - > ---------------------------------------------------------------------- > - > --------- > > 3 times among other exceptions in a span of around 2 minutes. > > 25th April '14: > > The errors captured in the logs were like, > ---------------------------------------------------------------------- > - > ---------------------------------------------------------------------- > - > --------- > java.lang.OutOfMemoryError: GC overhead limit exceeded This error specifically means that the JVM is basically spending all of its time doing garbage collection and not really getting any significant amount of memory back for its efforts. The end user experiences this usually as a hung system. It might eventually come back or it might end up with a different, more severe, OOM error. There are lots of various causes for this: too small memory allocation; too much load; an activity generating a lot of objects, most of which persist for a long time; memory leaks; or a combination of the above. How to address it? a) Profile what parts of the app are being used with this occurs and have the dev team look at what could be causing the problem. There might be a better way to perform the action requested. b) Increase the available memory (double it or more). This is only a band-aid and you may still have the problem, but less often. Have the dev team look for memory leaks. c) Anyone else with ideas? Jeff > ---------------------------------------------------------------------- > - > ---------------------------------------------------------------------- > - > --------- > > 4 times among other exceptions in a span of around 2 minutes. > > Requesting a reply on this. > > Regards __________________________________________________________________________ Confidentiality Notice: This Transmission (including any attachments) may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. 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