关键词：云计算；物理系统；资源分配
摘 要：Recently, there has been a dramatic increase in the popularity of cloud computing systems that rent computing resources on-demand, bill on a pay-as-you-go basis, and multiplex many users on the same physical infrastructure. These cloud computing environments provide an illusion of in nite computing resources to cloud users so that they can increase or decrease their resource consumption rate according to the demands.