Clustering plays an important role in Enterprise applications as it lets you split the load of your application across several nodes, granting robustness to your applications. As we discussed earlier, for optimal results it's better to limit the size of your JVM to a maximum of 2-2.5GB, otherwise the dynamics of the garbage collector will decrease your application's performance.
Combining relatively smaller Java heaps with a solid clustering configuration can lead to a better, scalable configuration plus significant hardware savings.
The only drawback to scaling out your applications is an increased complexity in the programming model, which needs to be correctly understood by aspiring architects.
JBoss AS comes out of the box with clustering support. There is no all-in-one library that deals with clustering but rather a set of libraries, which cover different kinds of aspects. The following picture shows how these libraries are arranged:
The backbone of JBoss...