Performance Evaluation of Cloud Systems by Switching the Virtual Machines Power Mode Between the Sleep Mode and Active Mode

Abstract

Data centers are cost-effective infrastructures for storing large volumes of data and hosting large scale service applications. Cloud computing service providers are rapidly deploying data centers across the world with a huge number of servers and switches. These data centers consume significant amounts of energy, contributing to high operational costs. In this chapter, we study energy savings of data centers by consolidation and switching off of those virtual machines which are not in use. According to this policy, c virtual machines continue serving the customer until the number of idle servers attains the threshold level d; then d idle servers take synchronous vacation simultaneously, otherwise these servers begin serving the customers. Numerical results are provided to demonstrate the applicability of the proposed model for the data center management in particular, to quantify theoretically the tradeoff between the conflicting aims of energy efficiency and Quality of Service (QoS) requirements specified by cloud tenants.