What is the SRB
The Storage Resource Broker (SRB) is a distributed file system (Global File System or Data Grid), based on a client-server architecture which presents the user with a single file hierarchy. It has features to support the management, collaboration, controlled sharing, publication, replication, transfer, and preservation of distributed data.
The SRB system is a middleware in the sense that it is built on top of other major software packages (various storage systems, real-time data sources, a relational database management system, etc) and it has callable library functions that can be utilized by higher level software. However, it is more complete than many middleware software systems as it implements a comprehensive distributed data management environment, including various end-user client applications.