A spin-up saved is energy earned: achieving power-efficient, erasure-coded storage

Storage accounts for a significant amount of a data center's ever increasing power budget. As a consequence, energy consumption has joined performance and reliability as a dominant metric in storage system design. In this paper, we show that the structure of an erasure code-- which is generally used to provide data reliability--can be exploited to save power in a storage system. We define a novel technique in power-aware systems called poweraware coding and present generic techniques for reading, writing and activating devices in a power-aware, erasurecoded storage system. While our techniques have an effect on energy consumption, fault tolerance and performance, we focus on a few examples that illustrate the tradeoff between power efficiency and fault tolerance. Finally, we discuss open problems in the space of poweraware coding.