On Optimal Policies for Energy-Aware Servers

As energy costs and energy used by server farms increase, so does the desire to implement energy-aware policies. Although under some metrics, optimal policies for single as well as multiple server systems are known, a number of metrics remain without sufficient knowledge of corresponding optimal policies. We describe and analyse a model to determine an optimal policy for on/off single server systems under a broad range of metrics that are based on expected response time, energy usage, and switching costs. We leverage this model in the determination of routing probabilities to show a range of nontrivial optimal routing probabilities and server configurations when energy concerns are a factor.