The Research On Strategy Of Multiple Replica In Distributed Environment

With the popularity of various application of Internet gradually improved in our dailylife, Global data are also exponentially growing, According to the survey of Internet data center, the global data has exceeded 2 trillion GB in 2011. In 2016, IBM’s vice President in a flash memory union meeting deemed that a new type of application as big data brings opportunity to the different industries, especially to the storage system in the field of IT.With the constant challenges and development of storage of big data, the difficulty in security of data storage is growing, especially in the data processing, transmission and storage and so on. Once the security problems appeared, the information such as the user’s personal privacy, friends’ contact, shopping records, and search habit will be dangerous.Facing the bottleneck of the capacity and safety in data storage, Blu-ray will solve these problems better. The blu-ray disc can easily expand capacity by means of increasing CD, and it can also manage the storage resources as the same level as PB or EB. Secondly, using the technology of RAID0、RAID5、RAID6, the security level can reach 19 N. This thesis will introduce blu-ray disc as the bottom storage devices to build storage system of mixed medium according to the principle of Bilfredo Pareto(a large number of I/O requests for visiting a few popular data, but the access frequencies of most unpopular data is very low).After introducing the blu-ray to the cloud storage system,the system will face some difficulties: how to ensure the consistency in the replica of the distributed system, how to solve the data migration in mixed medium,and the read or write consistency issues of caused by data migration. To solve these problems, the thesis is going to finish some works as follows:Firstly, The research and analysis of the consistency strategy of the existing replica, and explore a suitable strategy the same as replica for the storage of mixed medium. This strategy integrated with user settings, file access, copy information, and it can finish the update task of copy better.Secondly, The research and analysis of the online migration technology of the storage system, adopting the method of circular buffer to reduce access conflict, which can complete the online migration task better.