AN IMPROVED ENERGY-EFFICIENT DISTRIBUTED STORAGE SYSTEM
School of Information Management, Hubei University of Economics, Wuhan, China
Energy consumption has increasingly become a serious problem in contemporary data centres. The electricity bill contributes a significant fraction of the Total Cost of Ownership (TCO), and it is predicted to increase at an even faster pace in the following years as extremely large volume of data are being generated on a daily basis which would necessitate corresponding storage capacity to hold them. As a profitable work-around step toward the energy problem within the cloud infrastructure, in this paper, we propose REST, an energy-efficient cloud storage, which is built upon a cluster-based object store similar to GFS. It achieves high energy-efficiency by cleverly exploiting the redundancy already present in the system without compromising the inherently well-established schemes for consistency, fault-tolerance, reliability, availability, etc., while maintaining a reasonable performance level. By modifying slightly the data-layout policy, REST can safely keep a large amount of the storage nodes in standby mode or even powered off entirely most of the time. Deploying a sophisticated monitor, it also provides the flexibility to power up sleeping or powered down nodes when necessary to accommodate to the variations in workloads. Trade-offs between energy efficiency and performance can be conveniently made by simply adjusting a trade-off metric in REST. The FileBench and real world workload experimental results demonstrate that power savings can reach 29% and 33%, respectively, while still providing comparable or even surprisingly better performance.