WildFly – Performance tuning

If you run the RedHat Application Server WildFly in standalone configuraiton you can customize the Java VM options to do some performance tuning.

The VM Options

In different to GlassFish the VM Options can not be set from the WildFly Web Console. But you can change or add VM Options by changing the standalone.conf file in the /bin directory. (Note that this is not the same as the standalone.xml configuration inside the /stanalone/ folder!)

Typical values to use for a 3G RAM machine  are:


or for a machine with 4G RAM.


The JAVA_OPTS section in your standalone.conf file then should look like this:

# Specify options to pass to the Java VM.
if [ "x$JAVA_OPTS" = "x" ]; then
JAVA_OPTS="-Xms1024m -Xmx1024m -XX:MaxPermSize=256m -XX:NewRatio=2 -XX:PermSize=64m -Djava.net.preferIPv4Stack=true"
 JAVA_OPTS="$JAVA_OPTS -Djboss.modules.system.pkgs=$JBOSS_MODULES_SYSTEM_PKGS -Djava.awt.headless=true"
 echo "JAVA_OPTS already set in environment; overriding default settings with values: $JAVA_OPTS"

You can verify your new settings directly in the beginning of the output when starting your WildFly


 JBoss Bootstrap Environment
 JBOSS_HOME: /opt/wildfly-8.0.0.Final
 JAVA: java
 JAVA_OPTS: -server -XX:+UseCompressedOops -Xms1024m -Xmx1024m -XX:MaxPermSize=256m -Djava.net.preferIPv4Stack=true -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true


Database Pool

Also the Database Pool Configuration in WildFly is different to the settings in GlassFish. GlassFish comes with some useful default values. In WildFly you should add the following Pool Settings:

  • Min Pool Size = 5
  • Max Pools Size = 25
  • Share Prepared Statements = true
  • Statement Cache Size: 32


Session EJB Pooling

For some reason the pooling of stateless EJBs is disabled per default in WildFly. If you have  expensive initialization in your stateless session EJBs it is very useful to add pooling for that kind of beans. This can increase the performance of your application dramatically.

Edit the standalone.xml file in the WildFly /standalone/configuration/ directory and change the section “session-bean” like in the following example:

  <subsystem xmlns="urn:jboss:domain:ejb3:2.0">
                    <bean-instance-pool-ref pool-name="slsb-strict-max-pool"/>
                <stateful default-access-timeout="5000" cache-ref="simple" passivation-disabled-cache-ref="simple"/>
                <singleton default-access-timeout="5000"/>
                    <strict-max-pool name="slsb-strict-max-pool" max-pool-size="32" instance-acquisition-timeout="5" instance-acquisition-timeout-unit="MINUTES"/>
                    <strict-max-pool name="mdb-strict-max-pool" max-pool-size="20" instance-acquisition-timeout="5" instance-acquisition-timeout-unit="MINUTES"/>

See also: https://community.jboss.org/message/881747

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