Oasis: Scaling Out Datacenter Sustainably and Economically

As big data applications proliferate, datacenters today are increasingly looking to adopt a scale-out model. Nevertheless, power capacity has become an important bottleneck that restricts horizontal scaling of servers, especially in datacenters that oversubscribe power infrastructure. When a datacenter hits its ceiling for power provisioning, conventionally the owner has to either build another facility or upgrade existing infrastructure-both approaches add huge cost, require significant time, and can further increase carbon footprint. This paper proposes Oasis, a novel datacenter expansion strategy that enables power-/carbon- constrained servers to scale out economically and sustainably. The basic structure of Oasis, called Oasis Node, naturally supports incremental capacity expansion with near-zero environmental impact since it leverages modular solar panels and distributed battery systems to power newly added servers. To optimize the operation of newly added nodes, we further propose a management framework called Ozone. It allows Oasis to jointly perform power supply switching and server speed scaling to improve efficiency locally and globally. We implement a prototype of Oasis and use it as a research platform for evaluating the design tradeoffs of green scale-out datacenters. With Oasis, a green datacenter could gradually double its capacity with near-oracle performance, extended battery lifetime, and 26 percent cost savings.