A Quantitative Analysis of the Xen Virtualization Overhead

Recently, consolidation on virtual servers has gone from a small market to a massive industry migration which is affecting businesses across different kinds of companies. Virtualization can be useful to help IT organizations to reduce complexity and costs with management, ownership, and energy consumption, providing a flexible environment for the execution of IT services. In this context, understanding the main properties of the virtualization overhead and also quantifying this overhead is crucial for the deployment of applications in a virtual environment. In this work, we present a performance characterization of applications running on the Xen environment, aiming at identifying the most important aspects of the overhead imposed on applications by the virtual system. We use four benchmarks which stress different aspects of the virtual system. We compare the performance of the benchmarks on a single virtual machine (VM) against a Linux system and study the performance interference among VMs scaling on the same hardware platform. Our results explore the causes of this extra overhead and show that it can be significant.