November 10, 2003
This paper describes key issues for building an energy efficient peer-to-peer (P2P) storage system. Current P2P systems waste large amounts of energy because of the false assumption that participating nodes' resources are free. Environmentally and economically, this is not true. Instead this paper argues that idle nodes in a P2P system should sleep to save energy. We derive an upper bound on the time an idle node can sleep without affecting the durability of the data stored in the system. This upper bound is parameterized by the replication factor and expected failure rates. We also outline a protocol for failure detection in an environment where only a small fraction of the nodes are alive at any time.