As long as virtualization hits more companies, these start wondering differences between different approaches. Is not trying to compare apples with oranges, is more trying to recognize most effective solution for a specific task. It’s normal customers look for point of comparison, some focusing on perfomances while others on features set.
Who tried so far to compare most popular representatives of both approaches, typically VMware products on a side and SWsoft Virtuozzo on the other, failed greatly, because at the end of the day you are still matching apples with oranges.
Anyway the need to understand is more important than the risk to fail, so new comparisons are popping up.
Tim Freeman, starting from the announce of KVM inclusion in Linux kernel, does a notable research on the topic and highlights a very interesting paper from Princeton University, titled Container-based Operating System Virtualization: A Scalable, High-performance Alternative to Hypervisors, where Linux VServer is compared with Xen:
Hypervisors, popularized by Xen and VMware, are quickly becoming commodity. They are appropriate for many usage scenarios, but there are scenarios that require system virtualization with high degrees of both efficiency and isolation. Examples include HPC clusters, the Grid, hosting centers, and PlanetLab.
We present an alternative to hypervisors that is better suited for such scenarios. This approach is a synthesis of prior work on resource containers and security containers applied to general-purpose, time-shared operating systems. Examples of such container-based systems include Solaris 10, Virtuozzo for Linux, and Linux VServers.
This paper describes the design and implementation of Linux Vservers.as a representative instance of container-based systems.and contrasts it with Xen, both architecturally and in terms of effiency and support for isolation.
Read the whole paper here.