REST: A Redundancy-Based Energy-Efficient Cloud Storage System

Energy consumption has increasingly become a serious problem in contemporary data centers. The electricity bill contributes a significant fraction of the Total Cost of Ownership (TCO), and it has been predicted to increase at an even faster pace in the following years. In an attempt to reduce the energy consumption in cloud infrastructures, we propose REST, an energy-efficient cloud storage built upon an open source cluster-based object store similar to GFS. It achieves high energy-efficiency by cleverly exploiting the redundancy and its asymmetric accesses existing in the system without compromising inherent well-established mechanisms, while maintaining reasonable performance level. By slightly altering the data-layout policy, REST can safely keep a large amount of redundant storage nodes in standby mode or even powered off most of the time. Deploying a sophisticated real-time workload monitor, it provides flexibility to power up standby or powered down nodes to accommodate the variations in workloads. In addition, trade-offs between energy and performance can be conveniently made by simply adjusting a trade-off metric in REST. The File Bench experimental results have demonstrated that power savings can be as high as 29%, still providing comparable or even better performance.