The Research Of The Meta Information Management And Consistency In Data Grid

In recent years, volume of datasets in modern large-scale scientific researches, information services and digital media applications is growing explosively, and research about data grid technology becomes a new hotspot in the computer circle all over the world. Since 1990 some great progresses have been made about the basic theoretical research and test-bed environment construction in USA and European countries. Researches about the Grid computing technologies have been made.Our project focuses on the key technologies of data grid. According to the characteristic of data intensive application, we design and develop our own data grid called GridDaen. It adopts Java-based Web service mechanism to support standard service format, which make it a wide area network usable DataGrid. Now it has been deployed in the CNGrid environment to provide reliable and efficient data service.This paper studies the meta-information service in data grid, as an important part of the GridDaen system. On the basic of advance grid systems and their meta-information technologies, we design and realize a distributed meta-information system which can support different managing domains, called MIS. It is completed by using web service mechanism and JDBC database tools, providing friendly interface and easily used publish & discovery tools for users and APIs & SDK for programming. MIS provides some important services such as information publish & discovery, replica & management, multiple-domain security mechanism and system management. Therefore, grid users in different locations are provided with several useful features such as uniform logical view, single accessing interface and virtual collection mechanism. It shields the difference between diverse underlying resources and accesses data transparently, which can be a favorable supporting platform to exploit higher grid application.On the basis of the Meta information service research and realization above, a loose and ansyncronous replica consistency model in Grid environment is presented and designed. This model takes the real environment and charactatistic of resource autonomy as the point, to ensure the consistency between different replicas without the tremendous load on the resource and networks. Testing results indicate that it can really take advantage of the grid and enhance the total performance of the whole system, balance the load between resources, enhance the avalibility and robustness and give great support for the replica management.