A comparison of the performance and scalability of Xen and KVM hypervisors

Virtualization is the fundamental technology for corporate data center consolidation and cloud computing. Companies and academic institutions consolidate their servers through virtualization in search for efficient hardware resource usage, lower energy consumption, improved fault tolerance, and increased security. In this paper, we investigate the performance and scalability of two open source virtualization platforms: Xen and Kernel-based Virtual Machine (KVM). We analyze the influence of the number of virtual machines on the performance of several benchmarks that measure compute power, network, and I/O throughput. Virtual machines are running on top of a single physical host. The results show that these two virtualization solutions have similar behavior. An important degradation in the performance is noticed when the number of virtual machines equals or exceeds the number of physical core available. Hyper-threading boots the performance by a small margin. The effect of virtualization on I/O throughput is even more noticeable, although virtual machines were using LVM logical volumes as disk images in our tests.