My notes and Other stuff:: January 2014

JMX - Java Management Extensions

Enable remote access in tomcat. Include following options with JAVA_OPTS environment variables in tomcat start-up script.

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=8999
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.password.file=pw file path
-Dcom.sun.management.jmxremote.access.file=access file path
-Djava.rmi.server.hostname=(Optional)

You can place the password and permissions files in any location, such as "$CATALINA_HOME/conf/". Make sure to modify the permissions of these files so that they can only be viewed by users with appropriate access :

$ chmod 600 /path/to/pw/file
$ chmod 600 /path/to/access/file

Include in start-up scipt start_admin.sh

export CATALINA_OPTS="-XX:MaxPermSize=512m -Xms1024M -Xmx2048M -XX:NewRatio=3 -XX:MaxNewSize=700M -XX:-UseConcMarkSweepGC -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.password.file=$TOMCAT_HOME/conf/jmxremote.password -Dcom.sun.management.jmxremote.access.file=$TOMCAT_HOME/conf/jmxremote.access -Djava.rmi.server.hostname=$TOMCAT_HOST"

Process arguments

test@[49]/log% pargs -a 2288

2288: /usr/java1.6/bin/java -Djava.util.logging.config.file=/opt/ITREfdsc/tomcat/conf

argv[0]: /usr/java1.6/bin/java

argv[1]: -Djava.util.logging.config.file=/opt/ITREfdsc/tomcat/conf/logging.properties

argv[2]: -DthisProcess=CEPServer

argv[3]: -Djava.awt.headless=true

argv[4]: -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager

argv[5]: -XX:MaxPermSize=512m

argv[6]: -Xms1024M

argv[7]: -Xmx2048M

argv[8]: -XX:NewRatio=3

argv[9]: -XX:MaxNewSize=700M

argv[10]: -XX:-UseConcMarkSweepGC

argv[11]: -XX:+UseParNewGC

argv[12]: -XX:+CMSParallelRemarkEnabled

argv[13]: -Dcom.sun.management.jmxremote

argv[14]: -Dcom.sun.management.jmxremote.port=8999

argv[15]: -Dcom.sun.management.jmxremote.ssl=false

argv[16]: -Dcom.sun.management.jmxremote.authenticate=true

argv[17]: -Dcom.sun.management.jmxremote.password.file=/opt/ITREfdsc/tomcat/conf/jmxremote.password

argv[18]: -Dcom.sun.management.jmxremote.access.file=/opt/ITREfdsc/tomcat/conf/jmxremote.access

argv[19]: -Djava.rmi.server.hostname=ceb-zone

argv[20]: -Djava.endorsed.dirs=/opt/ITREfdsc/tomcat/endorsed

argv[21]: -classpath

argv[22]: /opt/ITREfdsc/tomcat/bin/bootstrap.jar

argv[23]: -Dcatalina.base=/opt/ITREfdsc/tomcat

argv[24]: -Dcatalina.home=/opt/ITREfdsc/tomcat

argv[25]: -Djava.io.tmpdir=/opt/ITREfdsc/tomcat/temp

argv[26]: org.apache.catalina.startup.Bootstrap

argv[27]: start

fdsc@ceb-zone[50]/opt/ITREfdsc/log%

Java SE 6 HotSpot[tm] Virtual Machine Garbage Collection Tuning

Java HotSpot VM Options

http://docs.oracle.com/javase/6/docs/technotes/guides/vm/gc-ergonomics.html

http://docs.oracle.com/javase/7/docs/technotes/guides/vm/gc-ergonomics.html

http://www.tomcatexpert.com/blog/2011/11/22/performance-tuning-jvm-running-tomcat

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-Djava.awt.headless=true

To use any AWT libraries in your server code on a machine that's not running a windowing interface

CATALINA_OPTS is immensely useful for setting debug parameters, Java memory settings, etc. One very common use is to set the system property java.awt.headless to true. Most graphical applications (like Jasper, JFreechart, LiquidOffice, StyleReport, etc.) will halt Tomcat when they render if something isn't done to disable display rendering, and this is by far the easiest method. (This problem occurs with most J2EE servers, not just Tomcat). Here's how to make this setting in UNIX.

http://en.wikipedia.org/wiki/Xvfb

http://www.oracle.com/technetwork/articles/javase/headless-136834.html

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-Djava.util.logging.config.file=/opt/ITREfdsc/tomcat/conf/logging.properties

-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager

To provide customised log file config. It is default behaviour of Tomcat and included in catalina.sh

http://app-inf.blogspot.com.au/2012/10/java-util-logging-behaviour-in-tomcat.html

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-XX:MaxPermSize=512m

The permanent space is where are stored the class, methods, internalized strings, and similar objects used by the VM and never deallocated.

-XX:PermSize specifies the initial size that will be allocated during startup of the JVM. If necessary, the JVM will allocate up to -XX:MaxPermSize.

For most applications the permanent generation is not relevant to GC performance. However, some applications dynamically generate and load many classes. For instance, some implementations of JSPs do this. If necessary, the maximum permanent generation size can be increased with MaxPermSize.

http://stackoverflow.com/questions/12114174/what-does-xxmaxpermsize-do

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-Xms1024M

-Xmx2048M

-Xms defines the initial size of the heap and -Xmx defines the maximum size of the heap.

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-XX:NewRatio=3

By default, the young generation size is controlled by NewRatio. For example, setting -XX:NewRatio=3 means that the ratio between the young and tenured generation is 1:3. In other words, the combined size of the eden and survivor spaces will be one fourth of the total heap size.

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-XX:MaxNewSize=700M

-XX:NewSize

http://qnatech.wordpress.com/2012/09/17/how-does-xxnewsize-xxmaxnewsize-effect-garbage-collection/

http://www.oracle.com/technetwork/java/hotspotfaq-138619.html#gc_pause

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