Improving consolidation of virtual machine based on virtual switching overhead estimation

In virtualized data centers, live virtual machine (VM) migration can increase energy efficiency by consolidating VMs on fewer servers. This problem is usually considered a Bin Packing Problem with server capacity constraints, such as CPU, memory and network bandwidth. In order to minimize the communication traffic within the data center network, existing research works used correlation-based strategy to consolidate VMs onto servers, which means that VMs with inter-traffic are consolidated as closely as possible, e.g. within a server or a rack. However, this strategy increases the traffic load of virtual switches on servers, and it causes a certain number of CPU cycles of servers to move traffic through virtual switches. A lack of consideration for the virtual switching overhead may increase the risk that VMs are not allocated enough resources, and consequently reduce VMs׳ performance. In this work, we conduct experiments to estimate the virtual switching overhead on server CPU resource, and based on the experiment results, we propose a virtual-switching-aware VM consolidation algorithm to address this problem. Experiments on representative data center workloads show that the overhead can occupy 10-30% of server׳s CPU resources. Additionally, our algorithm shows a much lower server capacity violation probability as compared with the baseline algorithm.