On Impact of Dynamic Virtual Machine Reallocation on Data Center Efficiency

Modern OS virtualization technology allows for "live migration" of virtual servers between physical hosts after the initial consolidation thus providing new avenues for performance optimization. This paper focuses on quantifying by how much data center efficiency can be improved using dynamic (i.e., in response to demand changes) real-location of virtual machines between physical servers. An analytical performance model of dynamic virtual machine reallocation is presented. It allows to estimate the reduction (as compared to the static consolidation) in the number of physical servers required to host the workload (under the same requirements of the maximum number of capacity overloads). Model is validated using simulations and several insights based on the analysis are provided.