Research Of Replica Placement Strategy In Cloud Storage System

In recent years, as computing, storage and communication technology development, global data is showing explosive growth. Cloud storage is a fundamental technology for information sharing and data service in the Internet faced with massive storage requirements of PB level. Data replica is widely used in a cloud storage system to improve data availability, enhance fault-tolerant capability and ameliorate system performance. Replica placement technology is key technology in cloud storage system’s data replication process. However, it also brings many other issues such as storage bandwidth overhead, layout of replica, load balancing.This paper design replica placement strategy from two different angles.(1) In order to solve load balancing issues in cloud storage system nodes, a cluster-based data replica strategy in cloud storage system is proposed in this paper. It includes when to replicate data, the number of its replicas and where these replicas should be placed, and in replica placement stage a Cluster Based Replication Placement(CBRP) method with load balance in cloud storage system is presented. Related Experiments demonstrated that this method is practical and with good performance.(2) Massive problem for small files that exist in the cloud storage system, this paper presents a small file memory model with read and write separation mode. A Data In Innode(D2I) replica placement strategy is designed based on the model, which includes hierarchical merging small files replica, mall files replica level settings and small file replica dynamic adjustment. Related simulation results show that replica placement policy which was proposed for small files can effectively improve the efficiency of the file reading and writing.And finally,this paper design and implement the cloud storage system.The corresponding database has also been designed. Replica placement strategy proposed in this paper is applied in the cloud storage system’s node control module and small file processing module. This provides storage services for OpenStack cloud management platform and realizes the basic functions of cloud storage.It actually prove the feasibility of the replica placement algorithm and stability of the systems.