Project : Simulator for multi-tiered web applications
Seunghwan Lim

Abstract
Nowadays, multi-tiered web applications are popular in web service configuration. Usually, people did analytical modeling on multi-tiered web applications. This analytical modelling is beneficial to predict the server capacity and understand the nature of multi-tiered web applications. Thus, it is used in provisioning facilities for a web service and configuring facilities. However, I would like to implement a simulator for multi-tiered web applications to understand the system more accurately. This multi-tiered web server simulator can be used to predict latencies and throughputs in each tier. With simulation, moreover, we can understand what kinds of behavior in each component is important to analysis the entire system's performance. In addition, perhaps, we can use this simulator to extrapolate the performance of a system which is hard to measure in real environment. I would like to implement three layered simulator. The most underlaying layer is network interface layer. This layer will capture the hardware. And the second layer is OS, linux, scheduler because I would like to simulate both TCP and Infiniband and one of the important difference between these two systems is context switch . The third is applications' behavior. I assume web server is the apache web server, application server is JOnAS, and the database server is mySQL. Since these applications are widely used and source code of them is open. Specifically, I would like to use CSim package to implement the simulation since I would see the CPUs, Disks and Network interfaces are as M/M/1 queues and CSim is great to build this kinds of simulation model. Moreover, CSim has been designed to empower C/C++ programmers so that it is easy to implement the behavior of linux scheduling and so on.

Below are some of publications which I read before to propose this project.

1. Gaurav Banga and Peter Druschel, Measuring the Capacity of a Web Server, Proceedings of the USENIX Symposium on Internet Technologies and Systems, 1997
2. Enrique V. Carrera, Srinath Rao, Liviu Iftode, and Ricardo Bianchini, User-Level Communication in Cluster-Based Servers, HPCA, 2002
3. Ronald P. Doyle, Jeffrey S. Chase, Omer M. Asad, Wei Jin, Amin M. Vahdat, Model-Based Resource Provisioning in a Web Service Utility, USITS, 2003
4. Deniz Ersoz, Exploring User-level communication in designing cluster-based data centeres, PhD Thesis, 2007, Penn State.
5. Xue Liu, Jin Heo and Lui Sha, Modelling 3-Tiered Web Applications, IEEE MASCOTS, 2005
6. Daniel A. Menasce, Web Server Software Architectures, IEEE Internet computing, 2003
7. Bhuvan Urgaonkar, Giovanni Pacifici, Prashant Shenoy, Mike Spreitzer, and Asser Tantawi, An Analytical model for Multi-tier Internet Services and Its Applications