The JBoss Enterprise Platform ships with four server configurations. You can choose which configuration to start by passing the -c parameter to the server startup script. For instance, command run.sh -c all would start the server in the all configuration. Each configuration is contained in a directory named jboss-as/server/[config name]/. You can look into each server configuration's directory to see the default services, applications, and libraries supported in the configuration.
The minimal configuration starts the core server container without any of the enterprise services. It is a good starting point if you want to build a customized version of JBoss AS that only contains the servers you need.
The default configuration is the mostly common used configuration for application developers. It supports the standard J2EE 1.4 and most of the Java EE 5.0 programming APIs (e.g., JSF and EJB3).
The all configuration is the default configuration with clustering support and other enterprise extensions.
The production configuration is based on the all configuration but with key parameters pre-tuned for production deployment.
The detailed services and APIs supported in each of those configurations will be discussed throughout this book. In this section, we focus on the optimization we did for the production configuration.
2.2.1. The production Configuration
To start the server in the production configuration, you can use the following command under Linux / Unix:
cd /path/to/jboss-as
RUN_CONF=server/production/run.conf bin/run.sh -c production
Or, you can simply copy the jboss-as/server/production/run.conf file to jboss-as/bin directory and start the server with run.sh -c production command. Below is a list of optimizations we specifically did for the production configuration:
In the jboss-as/server/production/run.conf file, we expanded the memory size of the server to 1.7 GB. We added the -server tag to JVM startup command on all platforms except for Darwin (Mac OS X). If the JVM is BEA jRockit, the -Xgc:gencon parameter is also added.
We configured the key generation algorithm to use the database to generate HiLo keys in order to generate the correct keys in a cluster environment (see deploy/uuid-key-generator.sar/META-INF/jboss-service.xml).
We removed the test JMS queues from deploy-hasingleton/jms/jbossmq-destinations-service.xml. Those queues are setup primarily for ease of application development. Production applications should configure their own JMS queues.
We set the ScanPeriod parameter to 60000 in conf/jboss-minimal.xml and conf/jboss-service.xml, so that JBoss AS does not spend too much time constantly scanning the deploy directory for new or updated deployments.
We removed the connection monitoring in deploy/jbossjca-service.xml. The connection monitoring feature helps catch unclosed connections that would otherwise cause leaks in the connection pools in development. However, it is a global point of contention that should be turned off (false) in production.
Logging is a big contention point in many production applications. In the production configuration, we removed the console logging and increased the logging level to WARN and ERROR for most packages. Please see details in conf/jboss-log4j.xml.
2.2.2. Further Tuning from the production Configuration
In addition to the standard optimization in the production configuration, there are a couple of simple techniques you can use to improve the performance and stability of your server.
The production configuration increases the JVM heap memory size to 1.7 GB. You should probably change it to fit your own server. For instance, if have a 64 bit server with several GBs of RAM, you can probably increase this value as long as you also use a 64 bit JVM. If your server has less than 2 GB RAM, you should decrease that value accordingly. In the production/run.conf file, the -Xmx and -Xms parameters specify the maximum and minimum heap sizes respectively. It is recommended that you set the -Xmx and -Xms to the same value to avoid dynamic re-sizing of the heap, which is a source of instability in many JVMs. You could also consider turing on parallel GC options if you are using the Sun JVM on a multi-core machine. The following is an example setup you might use a reference. Please see the Sun JVM documentation for more details on this startup parameters.
JAVA_OPTS="-Xms1740m -Xmx1740m -XX:PermSize=256m -XX:MaxPermSize=512
-XX:+UseConcMarkSweepGC -XX:+CMSPermGenSweepingEnabled
-XX:+CMSClassUnloadingEnabled"
In the embedded Tomcat module, you can turn off the development mode so that the server does not constantly monitor the changes in JSP files. To do that, edit the deploy/jboss-web.deployer/conf/web.xml file and add the development attribute to the JspServlet.
<servlet>
<servlet-name>jsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
... ...
<init-param>
<param-name>development</param-name>
<param-value>false</param-value>
</init-param>
... ...
In Tomcat, you could adjust the size of the thread pool. If you have multi-core CPUs or more than one CPUs on your server, it might be beneficial to increase the thread pool beyond the default 250. On the other hand, if you have a slow server, decreasing the thread pool will decrease the overhead on the server. The thread pool size can be adjusted via the deploy/jboss-web.deployer/server.xml file.
... ...
<Connector port="8080" address="${jboss.bind.address}"
maxThreads="250" maxHttpHeaderSize="8192"
emptySessionPath="true" protocol="HTTP/1.1"
enableLookups="false" redirectPort="8443" acceptCount="100"
connectionTimeout="20000" disableUploadTimeout="true" />
... ...
In addition, JBoss AS needs to use a relational database to store runtime data. In a production environment, you should use a production quality database to replace the embedded HSQL database. Please see Appendix B, Use Alternative Databases with JBoss AS for more information on how to setup alternative databases for the JBoss AS.
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