Automated dynamic redistribution of virtual operating systems under the xen virtual machine monitor

Operating system virtualization has recently become a popular technique to achieve better resource utilization in so-called '' server farm '' environments. This technique provides a virtual hardware interface on top of which one can run multiple instances of popular operating systems. The Xen Virtual Machine Monitor is an implementation of operating system virtualization that supports live migration, the transfer of a virtual operating system from one physical machine to another with minimal down time. We have utilized this capability to implement a monitoring and dynamic reconfiguration daemon that attempts to equalize the load on all host nodes in a group of machines running Xen. We have also implemented a simulator for testing balancing algorithms. Experiments using these tools have provided insight into the redistribution of virtualized operating systems and how this differs from the more thoroughly-studied problem of process-level load balancing.