Research On Resources Discovery In Grid Environment

Grid,which comes from the familiar Power Grid,is the great technological progress after the Internet and represents a kind of advanced technology and infrastructure.Grid aims at integrating all kinds of resources,which are geographically distributed and heterogeneous,in order to solve problems collaboratively.These resources include high performance computers,data servers, large-scale retrieval storage systems,virtual environment of visualization and so on. But the key of how to organize the distributed and dynamic grid resources is how to accomplish the discovery and location of them efficiently.Resource discovery takes a part of a bridge between resource requester and resource provider.With the help of resource discovery requesters can find proper resources from abundant and distributed grid resources conveniently.Resource location is a process of routing selection when the resource discovery was carried out and it is the key problem of resource discovery research.Therefore,the power of resource discovery and location has determined use factor and friendly degree directly in grid.First,the architecture of grid is described briefly in this thesis and the grid project Globus is introduced in detail.The advantages and disadvantages of the existing resource discovery mechanisms and methods are analyzed and compared. And based on the subject study,a layered and classified resource discovery model in grid environment is designed by integrating central and distributed resource discovery scheme.The model is composed of two layers,physical resource layer and virtual organization layer.In the virtual organization layer,grid resources are divided into some virtual organizations according to their different types,a manager node is set in every virtual organization to store and manage index information of all homogeneous resources in the physical resource layer.Therefore,on one hand,the problem of bottleneck in central scheme is avoided.On the other hand,the disadvantage in distributed scheme,the randomization and unstructured features of resources in information space,is avoided.And the effect and veracity of resource discovery increase.Moreover,corresponding locating strategy is designed based on the layered and classified resource discovery model in this thesis,and two locating situations,which include inside local and local to local,are taken into account.At last,resource discovery components are carried into effect by using the Globus Toolkit4.0 including description,information storage,information organization, request handing,selection about resources and programming implementation. Moreover,simulation is carried out to verify the feasibility and availability of the resource location strategy by OPNET.