Underprovisioning the Grid Power Infrastructure for Green Datacenters
Xu Zhou, Qiang Cao, Hong Jiang, Changsheng Xie · 2015
While there have been prior studies on underprovisioning the power distribution infrastructure for a grid-based datacenter, how to save grid capital investment by means of leveraging renewable energy to underprovision the grid power infrastructure in green datacenters remains largely an unexplored, open issue. Aggressively underprovisioning grid infrastructure can trigger power emergency in which simultaneous peak power draws across the datacenter exceed the tightly budgeted grid power capacity, leading to possible serious consequences including power shutdown. The resulting power emergency mandates a graceful reaction mechanism to sustain the power requirement to avoid power overdraw. While leveraging renewable energy in a green datacenter provides a possibility to prevent power overdraw during such a power emergency, the intermittent nature of renewable energy makes it a very challenging task because of the potentially unpredictable performance impact to individual applications. This paper addresses this issue by designing a novel renewable energy delivery infrastructure and considering performance consequences to individual applications of underprovisioning the grid power infrastructure in the presence of varied renewable power and limited battery's energy capacity in a datacenter. We build an experimental prototype to demonstrate such grid power underprovisioning on a cluster of 10 servers, with a simulated solar power generator. Using representative datacenter benchmarks to evaluate the effectiveness of the renewable solution in handling power emergencies, we show that renewable energy by itself can sustain different duration lengths of power emergency when its supply is sufficient. Batteries play an important role for performance boost when the supply of the renewable energy is insufficient. Our theoretical solution, in conjunction with workload migration, provides a seamless bridge across the whole spectrum of duration lengths of power emergency.