A scalable application server on Beowulf clusters : a thesis presented in partial fulfilment of the requirement for the degree of Master of Information Science at Albany, Auckland, Massey University, New Zealand

Application performance and scalability of a large distributed multi-tiered application is a core requirement for most of today's critical business applications. I have investigated the scalability of a J2EE application server using the standard ECperf benchmark application in the Massey Beowulf Clusters namely the Sisters and the Helix. My testing environment consists of Open Source software: The integrated JBoss-Tomcat as the application server and the web server, along with PostgreSQL as the database. My testing programs were run on the clustered application server, which provide replication of the Enterprise Java Bean (EJB) objects. I have completed various centralized and distributed tests using the JBoss Cluster. I concluded that clustering of the application server and web server will effectively increase the performance of the application running on them given sufficient system resources. The application performance will scale to a point where a bottleneck has occurred in the testing system, the bottleneck could be any resources included in the testing environment: the hardware, software, network and the application that is running. Performance tuning for a large-scale J2EE application is a complicated issue, which is related to the resources available. However, by carefully identifying the performance bottleneck in the system with hardware, software, network, operating system and application configuration. I can improve the performance of the J2EE applications running in a Beowulf Cluster. The software bottleneck can be solved by changing the default settings, on the other hand, hardware bottlenecks are harder unless more investment are made to purchase higher speed and capacity hardware

J2EE application for clustered servers : focus on balancing workloads among clustered servers : a thesis presented in partial fulfilment of the requirements for the degree of Master of Information Science in Computer Science at Massey University, Albany, New Zealand

J2EE has become a de facto platform for developing enterprise applications not only by its standard based methodology but also by reducing the cost and complexity of developing multi-tier enterprise applications. J2EE based application servers keep business logic separate from the front-end applications (client-side) and back-end database servers. The standardized components and containers simplify J2EE application design. The containers automatically manage the fundamental system level services for its components, which enable the components design to focus on the business requirement and business logic. This study applies the latest J2EE technologies to configure an online benchmark enterprise application - MG Project. The application focuses on three types of components design including Servlet, entity bean and session bean. Servlets run on the web server Tomcat, EJB components, session beans and entity beans run on the application server JBoss and the database runs on the database server Postgre SQL. This benchmark application is used for testing the performance of clustered JBoss due to various load-balancing policies applied at the EJB level. This research also focuses on studying the various load-balancing policies effect on the performance of clustered JBoss. As well as the four built-in load-balancing policies i.e. First Available, First Available Identical All Proxies, Random Robin and Round Robin, the study also extend the JBoss Load balance Policy interface to design two dynamic load-balancing policies. They are dynamic and dynamic weight-based load-balancing policies. The purpose of dynamic load-balancing policies design is to ensure minimal response time and obtain better performance by dispatching incoming requests to the appropriate server. However, a more accurate policy usually means more communications and calculations, which give an extra burden to a heavily loaded application server that can lead to drops in the performance

An electronic healthcare record server implemented in PostgreSQL

This paper describes the implementation of an Electronic Healthcare Record server inside a PostgreSQL relational database without dependency on any further middleware infrastructure. The five-part international standard for communicating healthcare records (ISO EN 13606) is used as the information basis for the design of the server. We describe some of the features that this standard demands that are provided by the server, and other areas where assumptions about the durability of communications or the presence of middleware lead to a poor fit. Finally, we discuss the use of the server in two real-world scenarios including a commercial application