Performance Evaluation of New Methods of Automatic Redirection for Load Balancing of Apache Servers Distributed in the Internet

An overloaded web server will lose incoming requests resulting in a “404 error” appearing at a client browser. Front-end application-level switches can redirect requests to less loaded servers. However, there exist no native methods within common web servers to automatically redirect requests for reducing load. We develop and evaluate changes to the open source Apache HTTP server to automatically redirect requests during periods of high load to a pre-specified overload server. We call the modified server “Red-Apache”. To reduce the double round-trip times of HTTP 301 redirection, a new “server tag” substitution method of redirection at a client browser is investigated. Server tag enables single round-trip redirection and is implemented by a JavaScript function in a returned page. Using the AB and SURGE benchmarks, we show that Red-Apache and server tag outperform the original Apache server and HTTP redirection, respectively.