Date Added: Mar 2011
Power consumption imposes a significant cost for data centers implementing cloud services, yet much of that power is used to maintain excess service capacity during periods of predictably low load. This paper investigates how much can be saved by dynamically 'Right-sizing' the data center by turning off servers during such periods, and how to achieve that saving via an online algorithm. The authors prove that the optimal offline algorithm for dynamic right-sizing has a simple structure when viewed in reverse time, and this structure is exploited to develop a new 'Lazy' online algorithm, which is proven to be 3-competitive. They validate the algorithm using traces from two real data center workloads and show that significant cost-savings are possible.