Power and QoS performance characteristics of virtualized servers

In this paper, we investigate power and QoS (Quality of Service) performance characteristics of virtualized servers with virtual machine technology. Currently, one of the critical problems at data centers with many thousands of servers is the increased power consumption. Virtual machines (VMs) are often used for Internet services for efficient server management and provisioning. While we expect that virtualized servers where multiple VMs run help save power, new issues in virtualized servers arise compared to conventional physical servers: migration of the load between servers and processor core assignment of the server´s workload from the viewpoints of QoS performance and energy consumption. Our experimental results show that server consolidation using VM migration contributes to power reduction without or with slight QoS performance degradation, and assignment of VMs to multiple processor cores running at a lower frequency can achieve additional power reduction on a server node.