A three-phase energy-saving strategy for cloud storage systems

•A mathematical model is formulated to describe the HDFS.•A replica management algorithm based on minimal replication factor is proposed.•A cost-based energy-saving algorithm is presented.•An energy-saving algorithm based on the state transition for the single data node is described.•Evaluation results are showed to demonstrate the energy efficiency of our proposed strategy.

In the running process of cloud data center, the idle data nodes will generate a large amount of unnecessary energy consumption. Furthermore, the resource misallocation will also cause a great waste of energy. This paper proposes a three-phase energy-saving strategy named TPES in order to save energy and operational costs for cloud suppliers. The three phases are replica management based on variable replication factor, cluster reconfiguration according to the optimal total costs and state transition based on observed and predicted workloads. These three phases save energy for the system at different levels which enhance the adaptability of our strategy. We evaluate our strategy using the expanded CloudSim toolkit and the results show that the proposed strategy achieves better energy reduction under different conditions in comparison with the existing schemes.