In this paper we develop, implement and evaluate an approach to quickly reassign resources for a virtualized utility computing platform. The approach provides this platform agility using ghost virtual machines (VMs), which participate in application clusters, but do not handle client requests until needed. We show that our approach is applicable to and can benefit different virtualization technologies. We tested an implementation of our approach on two virtualization platforms with agility results showing that a sudden increase in application load could be detected and a ghost VM activated handling client load in 18 seconds. In comparison with legacy systems needing to resume VMs in the face of sharply increased demand, our approach exhibits much better performance across a set of metrics. We also found that it demonstrates competitive performance when compared with scripted resource changes based on a known workload. Finally the approach performs well when used with multiple applic...
Wei Zhang, Hangwei Qian, Craig E. Wills, Michael R