Dynamic provisioning in next-generation data centers with on-site power production
Jinlong Tu, Lian Ying Lu, Minghua Chen, Ramesh K. Sitaraman · 2013
The critical need for clean and economical sources of energy is transforming data centers that are primarily energy consumers to also energy producers. We focus on minimizing the operating costs of next-generation data centers that can jointly optimize the energy supply from on-site generators and the power grid, and the energy demand from servers as well as power conditioning and cooling systems. We formulate the cost minimization problem and present an offline optimal algorithm. For "on-grid" data centers that use only the grid, we devise a deterministic online algorithm that achieves the best possible competitive ratio of 2αs, where αs is a normalized look-ahead window size. The competitive ratio of an online algorithm is defined as the maximum ratio (over all possible inputs) between the algorithm's cost (with no or limited look-ahead) and the offline optimal assuming complete future information. We remark that the results hold as long as the overall energy demand (including server, cooling, and power conditioning) is a convex and increasing function in the total number of active servers and also in the total server load. For "hybrid" data centers that have on-site power generation in addition to the grid, we develop an online algorithm that achieves a competitive ratio of at most Pmax(2--αs)/co+cm/L [1+2 Pmax--co/Pmax(1+αg], where αs and αg are normalized look-ahead window sizes, Pmax is the maximum grid power price, and L, co, and cm are parameters of an on-site generator.