Benckmarks: Xen 3.0.3 (unstable branch) vs OpenVZ for Linux kernel 2.6

After last month comparison of Xen 3.0.2 and OpenVZ for Linux kernel 2.6.16 made by Björn Gross-Hohnacker for his diploma thesis, this time is HP Labs’ turn to perform a benchmark analysis.

This new 14 pages document titled Performance Evaluation of Virtualization Technologies for Server Consolidation exposes a bigger overhead in Xen over OpenVZ:

In this paper, we evaluate two representative virtualization technologies, Xen and OpenVZ, in various configurations. We consolidate one or more multi-tiered systems onto one or two nodes and drive the system with an auction workload called RUBiS.

We compare both technologies with a base system in terms of application performance, resource consumption, scalability, low-level system metrics like cache misses and virtualization-specific metrics like Domain-0 consumption in Xen.

Our experiments indicate that the average response time can increase by over 400% in Xen and only a modest 100% in OpenVZ as the number of application instances grows from one to four. This large discrepancy is caused by the higher virtualization overhead in Xen, which is likely due to higher L2 cache misses and misses per instruction. A similar trend is observed in CPU consumptions of virtual containers. We present an overhead analysis with kernel-symbol-specific information generated by Oprofile…

Read the whole paper at source.