Gavin McCance -University of Glasgow 8A2DF4497C023635CC7D731F6ED4A9AB GROBID - A machine learning software for extracting information from scholarly documents
Replica Location Problem

Given a logical file identifier -how do we find all the replicas of that file on the Grid Driven by two use-cases: a) Particle physics -multiple replica of the same file so that the data are always near the compute resources -for data hungry applications b) Earth Observation/Medical -convenient mechanism for logical namespace. Don't need to know the physical location of the files.

Replica Metadata
Spitfire Sample API

Spitfire Sample API based upon common SQL operations. Use the Spitfire Grid service where you might have used JDBC before.

Provides DB query operations, update operations, and schema update operations.

Provides browser servlet to expose specific views of the data to web based clients.

Replica Location Service (RLS)Each site has a Local Replica Catalog LRC containing mappings for files located at the given site Each site runs a Replica Location Index RLI which contains a bloom-filter hashmap for all GUIDs in all LRCsArchitecture… Sequence to answer the query Bloom Filter Indexing RMC Spitfire: Technology DemonstratorLogical filename to storage (physical) filename mapping GUID Logical Alias Logical Alias Logical Alias Physical File Replica Physical File Replica Physical File Replica Physical File Replica Optimised to answer 2 very specific queries: "for a given GUID, give me all the replicas" "for a given GUID give me all locally available replicas" Scalability achieved by: Replica Location Index Local Replica Catalog Local Replica Catalog Local Replica Catalog Replica Location Index Replica Location Index Capabilities: Used to do GUID selection based on application-Advantages: Simple Grid-enabled front-end for any remote RDBMS specific metadata through secure Web Services (SOAP-RPC) High level of scalability Fast Not a memory intensive hash Subsequently use the RLS to find the physical replica based Provides sample generic RDBMS methods that may easily on the GUID be customized with little additional development Application Specific WSDL interfaces General Metadata Web Browser integration (data browser servlet) Replica Location Index Local Replica Catalog Local Replica Catalog Local Replica Catalog contact Replica Location Index to retrieve all LRCs Currently a centralised catalog GSI authentication Disadvantages: potentially having a mapping for the given GUID: GUID though work ongoing with Oracle Streams for replicated Local authorization module Only fulfills "EQUALTY" type queries, i.e. no wildcards architectures Not suitable for the retrieval of LARGE result sets List of LRCs Non-deterministic, i.e. there are a small number of false positives to be dealt with Work on clustering and replication for high availability Status: current version 2.1 solutions contact each LRC in the list to retrieve all replicas Used by EU DataGrid Earth Observation and Biomedical Replica Location Service Site 1 Site 2 Site 3 Site 1 Site 2 Site 3 Replica Metadata Catalog applications.
Architecture…Each LRC updates the RLI on every other site.for a given GUID, give me all locally available replicas simply contact the Local Replica Catalog.for a given GUID, give me all the replicas
Replica Metadata Catalog (RMC)

Stores GUID metadata: logical file names (human readable) small number of user-defined attributes ~O(10) Attributes are natively typed:

Future Work

Plan to work together with DAIS working group of GGF to ensure that our services can be re-factored into DAIS-compliant services.

Should be fairly easy since we are starting from web services.

Plan to work more closely with applications in order to refine the metadata interface, or just to enable their existing metadata applications to be 'on the Grid'.

Security modules
Authentication using standard GSI certs or proxies

Trustmanager checks validity and revocation

Role based Authorisation