Arquivamento Digital a Longo Prazo Baseado em Selecao de Repositorios em Redes Peer-to-Peer

Abstract

The importance of digital information is increasing constantly in today’s society. Digital libraries, Internet applications such email, photo sharing and Web site files often need to be preserved for a long-term and this is a responsability of digital archiving systems. This paper proposes a reliable replication model of immutable digital content to be used in long-term archiving systems. The archiving system is modeled as a set of storage repositories in which independent fail probabilities are assigned. Items are inserted in this system with a reliability that is satisfied replicating them in subsets of repositories. Through simulation, we evaluated three different strategies to create replicas. It is also proposed a totally distributed archiving system using this model over a peerto-peer (P2P) network. The communication between the nodes (repositories) of such network is organized in a distributed hash table and multiple hash functions are used to select repositories that will keep the replicas of each stored item. The system and its algorithms to create replicas are evaluated through experiments in a real environment. We believe that this model and the proposed algorithms, combined with the structured P2P scalability, make possible to construct a reliable and totally distributed digital archiving systems.