Understanding the Roles of Servers in Large-Scale Peer-Assisted Online Storage Systems

Online storage systems that provide versatile and convenient platforms for content distribution have attracted significant attention over the Internet. To guarantee adequate levels of service quality and to minimize server cost, such systems typically deploy dedicated servers while effectively utilizing peer bandwidth in a complementary fashion. It is essential to understand the role of servers and critical factors that influence the server contributions. In this paper, with full knowledge of internal mechanisms of a large-scale peer-assisted online storage system, namely FS2You, and large set of real-world traces, we examine the role of servers in such a system. Specifically, through analyzing server traffic volumes versus various critical factors including file popularity, time period (both "cold" and "hot" periods), and peer types, we not only reveal empirical observations that are contrary to general belief with in-depth rationales, but also exploit potential flaws of current design and strategy, which further draw practical implications on future design.