The Case for Medium-Sized Regional Data Centres

Cloud computing is widely associated with major capital investment in mega data centres, housing expensive blade servers and storage area networks. In this paper we argue that a modular approach to building local or regional data centres using commodity hardware and open source hardware can produce a cost effective solution that better addresses the goals of cloud computing, and provides a scalable architecture that meets the service requirements of a high quality data centre. In support of this goal, we provide data that supports three research hypotheses: 1. that central processor unit (CPU) resources are not normally limiting; 2. that disk I/O transactions (TPS) are more often limiting, but this can be mitigated by maximizing the TPS-CPU ratio; 3. that customer CPU loads are generally static and small. Our results indicate that the modular, commodity hardware based architecture is near optimal. This is a very significant result, as it opens the door to alternative business models for the provision of data centres that significantly reduce the need for major up-front capital investment.