Data Currency in Replicated Distributed Storage System

Application-level storage aggregation provides a massive storage capacity with high scalability and low cost. However, these systems usually only support their special sites, which ignores the legacy storage systems. So we developed a distributed storage system to aggregate these popular storages and provide a uniform access and management interface for these sites. To ensure high data availability, our distributed storage system utilizes a sophisticated way known as data replication. In this paper, we present the data currency scenario employed in our distributed storage system, which can be also used in other replicated distributed storage systems. We propose a replica access service (RAS) to deal with data availability and efficient retrieval of current replicas based on version controlling, which can balance the data accessibility and replica consistency. We validate our solution's performance and scalability through simulation up to 10,000 distributed sites. The simulation results show that our algorithm used in RAS achieves major performance gains, in terms of response time, compared with a baseline algorithm.