Energy costs are becoming the fastest-growing element in datacenter operation costs. Virtualization Technology has been employed increasingly widely in modern data centers in order to improve its energy efficiency. In particular, the capability of Virtual Machine (VM) migration brings multiple benefits for such as resources (CPU, memory, et al.) distribution, energy aware consolidation. However, the migration of virtual machines itself brings extra power consumption. For this reason, a better understanding of its effect on system power consumption is highly desirable.