Peer-to-peer (P2P) applications distribute large files fast. That makes them popular on the Internet and has motivated their use on datacenter networks. On datacenter networks, however, these Internet applications waste bandwidth. To fully use available bandwidth, we propose the P2P copy (PCP) application. Results with a prototype show that PCP reduces content distribution times by an order of magnitude. Categories and Subject Descriptors C.2.4 [Computer-Communication Networks]: Distributed Systems—Distributed applications General Terms Performance, Design, Experimentation Keywords P2P, datacenter network