ESG Services

ESG allows access to data that is stored either on rotating storage (currently at NCAR) or on deep storage (at NCAR MSS, NERSC HPSS and ORNL HPSS). A deep storage archive may occasionally be offline for scheduled mantainance or other administrative task.

The Storage Resource Manager (SRM) middleware is used to retrieve data from the deep archives and transfer it (via GridFTP) to the NCAR dataportal, where it is made available to HTTP requests.

The Replica Location Service (RLS) is a system of cross-updating databases that keeps track of files copies stored anywhere on the Grid. The RLS is used when publishing data to the ESG system.

The OpenDAPg server is used when requesting subsets of virtually aggregated datasets. The data is extracted from multiple files, stored into a single file, and made available to HTTP requests.