Access Protocols in Data Partitioning Based Cloud Storage

摘要

Existing share access protocols require the client to retrieve all shares even for read accesses in order to achieve atomic semantics. In cloud storage with widely distributed servers, this implies significant communication latency (from client to the farthest server) and additional network traffic. In this paper, we consider a nearby share retrieval approach to improve read performance. We first analyze the impact of this approach on the consistency semantics. Then we present the nearby share retrieval (NSR) protocol that satisfies regular semantics and guarantees wait-free reads. Experimental results show that our protocol yields significantly better read performance than existing protocols. To further optimize the performance of read accesses, we setup experiments to analyze the performance impacts of the number of shares to be retrieved in one round. Experimental results show that for most of the data, using the least required number (the threshold number in (n, k) data partitioning schemes) yields the best performance. But for hot data (with high access rates), access more servers in one round can achieve better performance.