Web Applications and Dynamic Reconfiguration in Unix Servers

During the past few years, a number of large Unix SMP Servers have added the support for partitioning and dynamic resource reconfiguration. One of the purposes of providing this technology is to support efficient, and dynamic resource management. In this paper we study the ability of Dynamic Reconfiguration (DR) to support changes in operational priorities and workload. For this purpose we use Websphere, composed of HTTP Server, Application Server and a Database, as the application. This application is a commonly used commercial product, and embodies a number of programming paradigms used in commercial computing; hence we use this application for our experiment. We treat this application as a black box to provide a realistic measurement of the efficacy of the DR technology in Unix Servers. We also use non parametric estimation techniques to study the jitters in our experimental data, and in this paper present a few of the derived conclusions. The main conclusions derived from this study are: 1) the resource allocations for a complex and function-rich
middleware system, such as Websphere, can be efficiently and dynamically managed by the DR technology, without middleware having to explicitly accommodate for the DR features of the operating system, and 2) the resource management system has to empirically monitor the throughput obtained from the application, rather than relay primarily on long time-scale estimations.