Hybrid web server: Traffic analysis and prototype

Web servers in small and medium enterprises (SME) consume a significant amount of energy. We consider how a hybrid SME web server based on two co-located platforms (one high performance and high power and the second low performance and low power) can be architected to appear as a single system image to clients. A prototype based on a Dell AMD Athlon x64-based PC and a Sheeva ARM-based plug computer is described and evaluated using the Apache ab benchmark. Using traffic traces from the KETI corporate web server, we show that for the majority of the time a low-performance platform can very likely meet the performance demands (during which time the high-power platform can sleep). We explore prediction of server load using network traffic analysis as a means to achieve a selection (or switching) policy between the two platforms. Using simple prediction methods, we show that we can achieve between 41% to 67% energy savings with minimal performance impact.