Date Added: Jan 2010
The recent popularity of Peer-to-Peer (P2P) systems for file sharing has led to increased demand for higher data availability from such systems. Measurements of popular P2P systems indicate that a large number of hosts appear to be available on a cyclic basis, and their availability shows great heterogeneity. This paper proposes a cooperative storage technique which employs erasure coding schemes on a collection of data objects and provides various levels of data redundancy. Based on this technique, the authors propose a history-based hill climbing scheme that takes advantage of varied time zones in a global system, and compare it to more conventional approaches to providing data availability. The simulation results show the improved data availability by this scheme.