Abstract
The importance of digital information is constantly increasing in the last years. Such information often needs to be preserved for a long-term and this is the responsibility 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 where each repository has an independent fail probability assigned to it. Items are inserted with a reliability that is satisfied by replicating them in subsets of repositories. Through simulation, we evaluated three different proposed strategies to create replicas. It is also proposed a completely distributed archiving system using this model over a structured peer-to-peer (P2P) network. The communication between the nodes (repositories) of the 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 is evaluated through experiments in a real environment. The proposed model and the algorithms, combined with the structured P2P scalability made possible the construction of a reliable and totally distributed digital archiving system.
