A low-cost, high-availability P2P storage scheme with regenerating code that combines caching methods

Abstract

Peer-to-peer (P2P) storage systems are expected to be fast, fault-tolerant, scalable, and reliable. Thus, high data availability is an essential feature of P2P storage systems. In this article, we present a scheme that utilizes a regenerating code (RC) with caching to improve the performance of content services provided by P2P storage systems. Erasure coding is commonly employed to support high availability, but this technique requires the original file to produce redundant data. In contrast, RC solves the problem by collecting the encoded information. However, RC requires more peers to decode the blocks, which is difficult in a P2P environment because more peers must simultaneously remain active to hold the file blocks. Based on the RC, we store the information for a peer that has recently accessed blocks and utilized the data in the peer's LRU cache to increase the access performance and reduce the encoding cost. We carried out a series of experiments with different cache sizes under various levels of P2P availability. The results show that our scheme can outperform the traditional RC system in terms of access performance, allowing access at least 83% of the time, while also achieving a lower cost.