“…Since the advantages of scalability and robustness of peer-to-peer system, a lot of peer-to-peer storage systems have been proposed such as Freenet (Clarke et al, 2000), OceanStore (Kubiatowicz et al, 2000), PAST , CFS (Dabek et al, 2001) and CFR (Lin et al, 2007). To keep a number of replicas all over the system, some of these systems implement their replication mechanisms with the need of global information.…”