Controlling the performance of 3-tiered web sites: Modeling, design and implementation

A method for controlling multiple-tiered Web site performance, both by bounding response times and preventing overload, was discussed. A completely self-tuning admission controller for 3-tiered websites based on classical control theoretic ideas was designed. The controller was implemented in the form of a proxy, called Yaksha. It was shown that Yaksha is able to bound response times for requests while maintaining a high throughput under overload.