Provided by: Columbia University
Date Added: Jan 2013
Cloud providers sell identically configured Virtual Machines (VMs) for the same price. Customers purchasing these VMs expect that they perform similarly and are allocated the same amount of virtual resources. In practice, however, the real performance of identically provisioned VMs depends on the underlying hardware, i.e., how the hardware is configured, and how much shared resources are consumed by co-located VMs. As workloads often have different resource requirements (e.g., CPU or disk I/O bound), a physical machine can be a better host to one VM than another, and swapping the locations of the two VMs can improve the performance (or any other metrics) of both VMs.