Some cloud storage services have recently introduced file versioning features by which more than one version of a file can be maintained. For providing file versioning with limited storage resources, it is essential to divide the resources among versions in accordance with the varied needs of numerous users. In this paper, we focus on applications in which newer versions of a file are more likely to be requested, which may be true in the case of many subscription services. We propose a new distributed data replication protocol supporting the file versioning feature. We also construct an analytical model that can derive an optimal allocation of the resources when the total number of replica nodes in a system and the distribution of the frequency of read requests for each version are given. In addition, we present some numerical examples obtained by simulations to show the good scalability and dependability of our system by assuming some realistic parameters.
['Takahiko Ikeda', 'Mamoru Ohara', 'Satoshi Fukumoto', 'Masayuki Arai', 'Kazuhiko Iwasaki']
A Distributed Data Replication Protocol for File Versioning with Optimal Node Assignments