iDARE: Proactive Data Replication Mechanism for P2P VoD System

Peer-to-peer (P2P) on-demand streaming systems inevitably suffer from peers churn that is the inherent dynamic characteristic of overlay network. With frequent peer departure, a large amount of media data cached on peer disk turns offline and unavailable, which becomes the major reason of heavy server load. To address the above issue, a new proactive data replication mechanism is proposed and implemented in existing P2P on-demand system GirdCast. Based on the new mechanism, peer can proactively replicate data chunks to stable cache servers for future sharing, when it has high possibility to leave the overlay. Two key heuristic algorithms are designed for departure prediction and replicated chunks selection. System trace driven simulation shows that the mechanism greatly decreases bandwidth load of media source server and improves the availability of chunks highly demanded but poorly provisioned by overlay peers.