Jan Storage Resource Broker Managing Distributed Data in a Grid A discussion of a paper published by a group of researchers at the San Diego Supercomputer Center, UCSD By: Nayef TRAD INSA-Lyon

2Jan PLAN What is SRB? SRB Features & Capabilities SRB Features & Capabilities SRB communication in conjonction with MCAT Federated SRB Zones Why Federation? Why Federation? Cons & Pros

3Jan What is SRB? SRB in a Nutshell A data grid solution A digital library A distributed but unified file system An advanced archival system A semantic Web A five nines availability resource broker

4Jan What is SRB? Features In depth The SRB is a client-server middleware that uses datasets to build a logical name space for referencing distributed data. The SRB provides a way to organize information stored on multiple heterogeneous systems into logical entities for ease of use. The SRB provides access to data stored on archival resources, file systems and databases. The SRB also provides capabilities to store replicas of data, controlling and auditing access to documents and collections, which is also known by logical-to-physical mapping hence Metadata Cataloging The SRB also provides a facility for co-locating data together using containers with more flexibility in accessing and updating files and stores user-defined metadata at different levels for better search capabilities.

5Jan What is SRB? SRB specific capabilities Support for the execution of remote operations. Access controls and audit trails to control and track data usage ( MCAT ) Interacting with multiple types of storage systems, for its abstraction User-friendly access through many ways like shells, scripts, libraries and web browsers

6Jan SRB & MCAT

7Jan SRB communication User SRB Server A SRB Server B Requesting a file 1 2 MES Contacting MES DB Server 3 Interpreting queries into SQL statements 4 Returning DB query 5 Supplying the location of the file 6 Contacting hosting server 7 Sending requested file

8Jan Federated SRB Zones DB SRB Zone A Zone B SRB DB Trust Relation SRB Zones recognize the presence of each others and is able to interact, despite the independency of each zone which is forming a federation. The overall federation is always viewed as a single logical namespace.

9Jan Federated SRB Zones Why Federation? Federation enables fragmentation of MCAT DataBase When a system failure occurs that would bring down an MCAT fragment, but shouldn’t affect the entire SRB, as the other sections will isolate the temporarily inaccessible server. When a system failure occurs that would bring down an MCAT fragment, but shouldn’t affect the entire SRB, as the other sections will isolate the temporarily inaccessible server. Federation permits MetaData to reside closer to the resource To reduce network latency, an MCAT server is hosted closer to the resource; in turn the SRB performance improves on a network span basis. To reduce network latency, an MCAT server is hosted closer to the resource; in turn the SRB performance improves on a network span basis. Federation enables the Virtual Organizations notion and makes it easier to merge newbies to the network, not to forget the ability of transferring and replicating documents across VOs

10Jan Cons & Pros Cons That paper can be considered as a fine support for understanding the Data Grids Architecture. Experiencing such enormous projects describes the powerful and huge capabilities of an SRB. Pros Absence of citation of some important points, like SRB federation and MCAT. Redundancy of similar ideas and information along the examples discussed.

11Jan Some Useful References

12Jan Here come troubles… Show me some MERCY while SHOOTING your questions Thank you !