Performance Isolation of a Misbehaving Virtual Machine with Xen, VMware and Solaris Containers

In recent years, there have been a number of papers comparing the performance of different virtualization environments for x86 such as Xen, VMware and UML. These comparisons have focused on quantifying the overhead of virtualization for one VM compared to a base OS. In addition, researchers have examined the performance degradation experienced when multiple VMs are running the same workload. This is an especially relevant metric when determining a systems’ suitability for supporting commercial hosting environments – the target environment for some virtualization systems. In such an environment, a provider may allow multiple customers to administer virtual machines on the same physical host. It is natural for these customers to want a certain guaranteed level of performance regardless of the actions taken by other VMs on the same physical host. In that light, another key aspect of the comparison between virtualization environments has received less attention how well do different virtualization systems protect VMs from misbehavior or resource hogging on other VMs? In this paper, we present the results of running a variety of different misbehaving applications under three different virtualization environments VMware, Xen, and Solaris containers. These are each examples of a larger class of virtualization techniques namely full virtualization, paravirtualization and generic operating systems with additional isolation layers. To test the isolation properties of these systems, we run six different stress tests a fork bomb, a test that consumes a large amount of memory, a CPU intensive test, a test that runs 10 threads of IOzone and two tests that send and receive a large amount of network I/O. Overall, we find that VMware protects the well-behaved virtual machines under all stress tests, but sometimes shows a greater performance degradation for the misbehaving VM. Xen protects the well-behaved virtual machines for all stress tests except the disk I/O intensive one. For Solaris containers, the well-behaved VMs suffer the same fate as the misbehaving one for all tests.