Shima Sokout jahromi - M.S, Department of Computer Engineering, Collage of Engineering, Fars Science and Research Branch, Islamic Azad University, Fars, Iran
Mansourr Aminilari - Assistant professor, Department of Computer Engineering, Collage of Engineering and Information Technology, Fars Science and Research Branch, Islamic Azad University, Fars, Iran
Amin Tousi - Faculty member, Department of Computer Engineering, Collage of Engineering, Fars Science and Research Branch. Islamic Azad University, Fars, Iran

Data centers are one of the major components of ICT field that have had significant growth to meet the needs of this area. In addition, the data centers are a computational resource for cloud computing and to have a good response time for a large number of their customers are often comprised of thousands of servers. In such a large scale, the energy consumption of data centers has increased extraordinarily. Increasing the power of consumption leads to increasing operational costs as well as greenhouse gas emissions. Thus, optimizing energy consumption in data centers is essential to reduce operational costs and protect the environment. Servers consume considerable amount of energy in cloud data center, thus optimizing the energy consumption of them has a significant role in reducing energy consumption. This paper provides a comprehensive study of the green metrics in the fields of energy efficiency in data centers, then classifies energy optimization approaches of servers in the data center and also provides a comprehensive review of techniques and their applications in each approach of recent research.

cloud computing, data center, energy efficiency, performance metric