Intra-Disk Parallelism: An Idea Whose Time Has Come

Power is a big problem in data centers and a significant fraction of this power is consumed by the storage system. Server storage systems use a large number of disks to achieve high performance, which increases their power consumption. In this paper, the authors propose to significantly reduce the power consumed by the storage system via intra-disk parallelism, wherein disk drives can exploit parallelism in the I/O request stream. Intra-disk parallelism can facilitate replacing a large disk array with a smaller one, using the minimum number of disk drives needed to satisfy the capacity requirements. They show that the design space of intra-disk parallelism is large and present a taxonomy to formulate specific implementations within this space.