Persistence service for non-persistent P2P systems

Abstract

Ensuring content persistence with minimal replication overhead is a prerequisite for providing any consistent service over a peer-to-peer (P2P) overlay. This paper introduces S-DATA, a bandwidth efficient protocol for achieving highly available P2P systems with minimal replication overhead. When considering a global P2P system, the cyclic behaviour of peers situated at different time zones can be found complementary of one another. In S-DATA, peers with complementary diurnal availability patterns collaborate in small replication groups and host each other's content in turn to ensure 24/7 availability. In this work we present a mathematical model for measuring time-base availability with (β - 1) redundancy as a function of replication group size and peer uptime behaviour. We also simulate the S-Data protocol in the PeerSim simulator and compare its performance against a few other time-based replication protocols.