2 Use of Metadata in e-Science For scientists, not only data itself but also its metadata is very important. Example of metadata: data ID, locations of data, experiment materials, instruments, and methods Relationships between data are described as metadata.
3 Example of Metadata Metadata is often described with hierarchical representation in many sciences. CMSATLAS run1run2 track1track2 Protein Nucleotide Primate Plant gb|AY BacteriaSequenceStructure sp|P37231pdb|1FM6 Vertebrate High Energy PhysicsMolecular Biology
4 Metadata Management using File Catalog Currently metadata are mainly stored in File Catalogs using their hierarchical namespace functionality. gLite: LFC, Fireman iRODS (SRB): MCAT Globus: RLS NAREGI: Gfarm File Catalog information of different Grid middlewares do not have compatibility to each other. It is not easy to exchange metadata over different Grid middlewares.
5 Resource Namespace Service (1) RNS lets you map any resource into single, hierarchical namespace Resources are referred to in a form of EndpointReference (WS-Addressing) RNS Specification is published as GFD- R-P.101 RNS implementation is available from U.Virginia and U.Tsukuba.
6 Resource Namespace Service (2) Hierarchical namespace management that provides name- to-resource mapping Basic Namespace Component Virtual Directory Non-leaf node in hierarchical namespace tree Junction Name-to-resource mapping that interconnects a reference to any existing resource into hierarchical namespace /grid ogfjp datagfs file1file3 file2 file4 file1file2 EPR1 EPR2 EPR: Endpoint Reference
7 Comparison RNS with File Catalog GFS Naming Profile on top of RNS and File Catalog Service are basically the same File Catalog implies loosely coupled federation, whereas File System Directory implies rather tightly coupled federation File Catalog Standardization is required by many parties
8 Data Grid Federation with RNS (Plan) RNS can interconnect a reference to any existing resource into hierarchical namespace Most of Grid middlewares have GridFTP for data transfer Use RNS as a (standardized?) File Catalog Use GridFTP URL gsiftp://.../ as the address of Endpoint Reference. gLite File Server (SRM) RNS iRODS File Server NAREGI File Server (Gfarm) Globus GridFTP Server Client (1) query (2) EPR list (including address) (3) Access with GridFTP protocol RNS
9 Summary RNS has a potential functionality to federate Data Grids over different middlewares. The federation encourages scientists to proceed international collaboration. RNS implementation is available. It need to be re-designed towards production level.