WAS v8.0 > Install the application serving environment > Distributed operating systems > Plan the WAS product installation
Example: Choosing a topology for better performance
Use this page to understand the advantages and disadvantages of various Workload Management topologies.
WAS provides various Workload Management (WLM) topologies. First, this topic describes a single-tier topology and a split-tier topology. Secondly, these two topologies are compared to show how the type of topology you choose can affect performance, security, and system flexibility.
The single-tier topology contains a cluster of WASs. Each cluster member contains a web container and an EJB container. The split-tier topology consists of a cluster of web container machines in front of a cluster of EJB container machines. The number of WASs machines is the same in both topologies; the client driver, the Web server with plug-in, and the back end database are located on separate, dedicated machines.
The single-tier topology has an (the performance) advantage because the web container and EJB container are running in a single JVM. In this topology, with object request broker (ORB) pass by reference enabled, the EJB processing is done on the same thread as the web container processing. In the split-tier topology, the ORB pass by reference option is ignored because the web container and EJB container are in separate JVMs.
The split-tier topology enables web and EJB resources to be isolated and separately administered.
A lab experiment using a the Benchmark Sample for WebSphere (Trade3) and a cluster of 6 applications servers found that throughput of the single-tier topology was 10-20% higher than that of the split-tier topology. We can download the Benchmark sample for WebSphere (Trade3) from the following website:
http://www-306.ibm.com/software/webservers/appserv/was/performance.html