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The San Diego Supercomputer Center (SDSC) at UC San Diego has released the production version of Zone SRB, version 3.0.1 of the widely-used SDSC Storage Resource Broker (SRB) middleware package. Zone SRB provides peer-to-peer federation of SRB collections, and provides increased performance and capabilities to support large-scale collaborations, allowing scientific users to flexibly share data and descriptive metadata across different SRB Metadata Catalog (MCAT) installations, or zones. SDSC SRB version 3.0.1, the user manual, and release notes are available to the research community for download as a source distribution at http://www.npaci.edu/DICE/SRB/.

The SDSC SRB data management middleware provides a uniform interface for connecting to heterogeneous data resources over a network. With more than 3,000 users at over 50 institutions, this SDSC client-server infrastructure solves the growing data management problems in today's scientific research.

"The production release of SRB version 3.0.1 makes available to users the full benefits of Zone SRB to federate multiple metadata catalogs," said Reagan Moore, co-director of the Data and Knowledge Systems program at SDSC. "This enables both local autonomy and collaborations that can scale much larger in collection size, geographical distribution, and number of participants."

New features in version 3.0.1 include backward compatibility for improved interoperability between SRB versions 2 and 3, and enhancements to improve performance, improve zone management, and organize collections. "Researchers can use version 3.0.1 of the SRB Server with version 2.x of the MCAT Metadata Catalog," said Arcot Rajasekar, director of the DAKS Data Grids Technologies group at SDSC. "This gives users more flexibility about when to upgrade their MCAT database." Although using the SRB Server with version 2.x MCATs will lack the Zone features, it will have all other SRB 3 features. SRB 3.0.1 Server will also recognize SRB 2.x clients, so users can update clients when they wish.

The Windows GUI interface inQ 2.x will work with SRB Server 3.0.1 and MySRB now operates with SRB 3.x and can display Zone information. In addition, the SRB Java API, Jargon, has been updated to operate with SRB 3

Version 3.0.1 relieves users of having to deal directly with much of the complexity of accessing large, distributed collections. When a user says, "Get me collection X," the SRB accesses the collection, no matter what sites and resources it's distributed across, even if part of the collection is in a container and part isn't. The intelligent middleware will also decide which replicas of the data are the most efficient to access, with all of these intricacies hidden from the user -- making the SRB even easier to use.

Another feature that has been added in version 3.0.1 is a GUID, or Global Unique IDentifier. Users can choose to have a GUID generated for each data object in a collection as a unique identifier, not only within a given SRB collection but extending across outside systems. "Having a unique identifier and global name space has long been a strength of the SRB within its own collections," said Rajasekar. "This new capability extends this feature beyond SRB collections, eliminating possible ambiguities and enabling interoperation with external Grid software systems."

Zone SRB is already being used in research such as the BaBar high energy physics project, where it has been adopted for production use in managing and moving multiple terabytes of data among sites around the world. The international high energy physics experiment Compact Muon Solenoid, or CMS, which must manage, share, and move terabytes of data around the world, is also making use of Zone SRB at some 20 sites that have large data collections and many users.

SDSC SRB Version 3.0.1 is supported on a wide variety of systems. The MCAT Metadata Catalog runs on Oracle, IBM DB2, Sybase, and Postgres. The SRB Server runs on Microsoft Windows NT, 2000,and XP, as well as most UNIX platforms including Linux and MacOS X, and supports data in file systems, tape stores, and databases. In addition to UNIX clients, there is a Windows graphical user interface, inQ, and a Web interface, MySRB.

The SRB team, led by Reagan Moore and Arcot Rajasekar, includes Mike Wan as chief architect, senior developers George Kremenek and Wayne Schroeder, as well as Sheau-Yen Chen, Charles Cowart, Lucas Gilbert, Arun Jagatheesan, Roman Olschanowsky, Antoine de Torcy, Tim Warnock, and Bing Zhu. - Paul Tooby