Book Image

JBoss AS 5 Performance Tuning

By : Francesco Marchioni, Jason Savod
Book Image

JBoss AS 5 Performance Tuning

By: Francesco Marchioni, Jason Savod

Overview of this book

Today's organizations need to deliver faster services to a large set of people and businesses. In order to survive this challenge, enterprises need to optimize the performance of their application server along with its components and hardware. Writing faster applications is no longer just an option for your products; it's an imperative requirement, which you cannot ignore. JBoss AS 5 Performance Tuning will teach you how to deliver fast applications on the JBoss Application Server and Apache Tomcat, giving you a decisive competitive advantage over your competitors. You will learn how to optimize the hardware resources, meeting your application requirements with less expenditure.The performance of Java Enterprise applications is the sum of a set of components including the Java Virtual Machine configuration, the application server configuration (in our case, JBoss AS), the application code itself and ultimately the operating system. This book will show you how to apply the correct tuning methodology and use the tuning tools that will help you to monitor and address any performance issues. By looking more closely at the Java Virtual Machine, you will get a deeper understanding of what the available options are for your applications and how their performance will be affected. You will learn about thread pool tuning, EJB tuning, JMS tuning, Enterprise Java Beans, and the Java Messaging Service. The persistence layer and JBoss Clustering service each have a chapter dedicated to them as they are two of the most crucial elements to configure correctly in order to run a fast application. You will also learn how to tune your web server, enabling you to configure and develop web applications that get the most out of the embedded Tomcat web server.
Table of Contents (17 chapters)
JBoss AS 5 Performance Tuning
About the Author
About the Reviewers
A Tuned Mind

Choosing the JVM settings

You can control the JVM heap settings using a set of parameters known as non-standard options, which are prefixed by the –X flag. Our analysis will be split into three main areas:

  1. At first, we will review the parameters that define the minimum and maximum heap sizes.

  2. After that, we will inspect the flags which can be used to fine-tune the Young /tenured generation ratio.

  3. Finally, we will examine the most complex part, which concerns the garbage collector behavior and that can be further optimized by choosing the optimal garbage collector algorithm.

Setting the correct heap size

You can configure the desired heap size using two switches: the –Xms option lets you decide the initial heap size. On the other hand, the –Xmx option is where you can set the maximum memory granted to the heap. If JVM tries to reclaim more memory when the maximum heap size is reached, a message saying java.lang.OutOfMemoryError: Java heap space is issued.

For example, the following command launches...