The Versioning System Balancing Data Amount and Access Frequency on Distributed Storage System

In this paper, a method of balancing both access frequency and data amount for a distributed parallel storage system under version management is discussed. We assume the version management method keeps the latest version of file and a number of differential information sets to access previous versions. Since the access frequency for an aged version is tend to be lower than that for the latest version, we control the access frequency distribution by the placement of the latest versions, while the data amount distribution is managed by the placement of the differential information whose size is enough small to adjust the subtle difference of data amount. We propose a distributed directory structure and data placement algorithm, and evaluate its effect on the access frequency and data amount distribution.