A decision support system for tuning Web servers in distributed object oriented network architectures

Abstract

Web technologies are currently being employed to provide end user interfaces in diverse computing environments. The core element of these Web solutions is a Web server that is based on the Hypertext Transfer Protocol (HTTP) running over TCP/IP. Web servers are required to respond to millions of transaction requests per day at an "acceptable" Quality of Service (QoS) level with respect to the end-to-end response time and the server throughput. In many applications, the server performs significant server-side processing in distributed, object-oriented (OO) computing environments. In these applications, a Web server retrieves a file, parses the file for scripting language content, interprets the scripting statements and then executes embedded code, possibly requiring a TCP connection to a remote application for data transfer. In this paper, we present an end-to-end model that addresses this new class of Web servers that engage in OO computing. We have implemented the model in a simulation tool. Performance predictions based on the simulations are shown to match well with performance observed in a test environment. Therefore, the model forms an excellent basis for a Decision Support System for system architects, allowing them to predict the behavior of systems prior to their creation, or the behavior of existing systems under new load scenarios.