Chapter 9: High-Volume Web Site Performance Simulator for WebSphere

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Overview

Executive summary: Clearly, more and more of your customers and employees are doing business on the Internet. Will your Web site ever be fast enough? Is there an affordable combination of hardware and software that will help you meet your response time targets? How can you know? Can you know ahead of time? How can you predict volumes when volumes are increasing but remain unpredictable?

And it's not just about response time. Today's sites are typically multi-tiered and employ both horizontal and vertical scaling techniques. Each tier can contain different hardware from multiple vendors. The software and middleware used can be as diverse as the hardware. The challenge to relate performance of different combinations is considerable.

To address these tough questions, IBM uses its High-Volume Web Site Performance Simulator for WebSphere. The HVWS Simulator is an analytic queuing model that estimates the performance and capacity of a Web server based on workload patterns, performance objectives, and specified hardware and software. It contains predefined workloads built with measurements of a variety of actual online customer applications including shopping, trading, banking, and others. The simulator includes special algorithms for sites with highly variable traffic and can perform 'what if' analyses of performance and capacity. The simulator also has algorithms to recommend the optimum configuration for a given workload and specified objectives.

The HVWS Simulator is updated regularly to support the most current hardware and software and additional workloads. IBM customers validate the simulator's models and algorithms during design, development, and test of each version. Many IBMers worldwide are trained to use the simulator to assist their customers in estimating what configuration will perform best for their specific workload type and volume. This chapter introduces the technology and use of the simulator.

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