Page 281 - Cloud computing: From paradigm to operation

Framework and requirements for cloud computing 1

Appendix III

Power management in cloud infrastructure
(This appendix does not form an integral part of this Recommendation.)

Datacentres are amongst the highest consumers of electricity all over the world. One distinct advantage of
cloud computing is it is also able to power-manage hardware and devices. Therefore, the resources in a cloud
infrastructure are recommended to be dynamically power-managed. The resources in cloud infrastructure
are often arranged in trees. As some resources of a cloud infrastructure become idle, it can decrease power
twigs or branches on trees. As the resource usage trends of cloud infrastructure are measured and controlled,
it would be possible for these networks to put energy back into the grid by providing the grid with accurate
time-based predictions of energy use. The grid can use this information to redirect energy to other
destinations, or make other intelligent decisions.

Power management in cloud infrastructure represents a collection of processes and supporting technologies
geared towards optimizing datacentre performance against cost and structural constraints. This includes
increasing the deployable number of servers per rack when racks are subject to power or thermal limitations
and making power consumption more predictable and easier to plan for.
Power management in cloud infrastructure comes in two categories: static and dynamic. Static power
management deals with fixed power caps to manage aggregate power, while policies under dynamic power
management take advantage of additional degrees of freedom inherent in virtualized cloud datacentres, as
well as the dynamic behaviours supported by advanced platform power management technologies.

273