Self-organized Data Redundancy Management for Peer-to-Peer Storage Systems

Abstract

In peer-to-peer storage systems, peers can freely join and leave the system at any time. Ensuring high data availability in such an environment is a challenging task. In this paper we analyze the costs of achieving data availability in fully decentralized peer-to-peer systems. We mainly address the problem of churn and what effect maintaining availability has on network bandwidth. We discuss two different redundancy techniques-replication and erasure coding-and consider their monitoring and repairing costs analytically. We calculate the bandwidth costs using basic costs equations and two different Markov reward models. One for centralized monitoring system and the other for distributed monitoring. We show a comparison of the numerical results accordingly. Depending on these results, we determine the best redundancy and maintenance strategy that corresponds to peer's failure probability.

A Comparative Study of Rateless Codes for P2P Persistent Storage

“…A data storage architecture based on a compound of Online coding and full replication has been recently proposed in [8]. Previous analyses have shown the benefit of hybrid replication over full replication in terms of data availability, storage overhead, and bandwidth usage [4,9]. However, for the best of our knowledge, no experimental study comparing the two classes of fountain codes has ever been performed.…”