Supporting efficient video file streaming in P2P cloud storage

Abstract

Peer-to-Peer cloud storage has emerged as an alternative to address the high installation and maintenance costs in conventional cloud storage based on client/server architectures. Since P2P cloud storage must guarantee the same level of data availability as conventional cloud storage, it has employed replication and erasure coding to redundantly store data among peers in P2P environments where the peer churn rate is high. However, most studies using two techniques have focused only on increasing data availability. Especially for video files stored in P2P cloud storage, in addition to guaranteeing their availability, it is critical but challenging to ensure that they are played back in real time by video player applications as if they were being read from local storage. To address this challenge in this paper, we propose a novel hybrid redundancy scheme to support efficient video file streaming while ensuring the availability of video files in P2P cloud storage. The main contributions of our work are threefold. First, we can achieve higher storage efficiency and better streaming performance by employing both erasure coding and replication simultaneously. Second, we can maximize the number of concurrent playback requests supported while minimizing the decrease in file availability by dynamically adjusting the redundancy degree of each video file according to its popularity. Third, we can further improve the performance by efficiently using storage space with our proposed two-phase replacement policy. Finally, we demonstrate through extensive experiments that our scheme outperforms other techniques by utilizing the benefits of both replication and erasure coding.