VCSP: virtual CPU scheduling for post-copy live migration of virtual machines

Abstract

The live migration of virtual machines among physical machines aims at efficient utilization of resources, load balancing, maintenance, energy management, fault tolerance, sharing resources and mobile computing. There are several methods for the live migration of virtual machines. In the post-copy approach, a virtual machine starts working in a target host, when data that is not present in the target machine is requested, a page fault occurs and the processing stops in the target until the arrival of the requested information. Certainly, the number of stops and lags negatively affects the system downtime. The reduction of physical or virtual CPU frequency is one of the techniques recommended to efficient migration of virtual machines. The modification of the frequency of physical and/or virtual CPU has already been used in the improvement of the pre-copy method to manage the speed of changes in the source machine. This paper presents the virtual CPU scheduling for post-copy (VSCP) framework that reduces the speed of the virtual CPU in post-copy to make a balance between processing speed of pages in the target machine and their transmission speed in the source machine. The VCSP is also compared with the baseline methods of the post-copy-prefetching and post-copy. In the experiments, the system downtime, total migration time, total pages transferred and throughput of system are evaluated. The results indicate that the proposed method improves the system downtime up to 8.17%, total migration time up to 30.33%, total pages transferred up to 54.49% and throughput of system up to 23.65%.