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09/11/2006, 10:30 AM - 12:00 PM
Speakers:
Amy Krause, Applications Consultant, EPCC.
Mike Jackson, Dr., University of Edinburgh.
OGSA-DAI is a middleware product designed to support data access and integration within an extensible framework. This session will provide a developer-centric overview of OGSA-DAI:
o Data access and integration requirements for Grids
o How OGSA-DAI aims to satisfy some of these requirements
o From data services to data resources - the OGSA-DAI architecture
o Customising OGSA-DAI for application-specific ends
o Effective deployment of OGSA-DAI
o Results of recent performance analyses
Attendees will acquire an understanding of key OGSA-DAI concepts and
the suitability of OGSA-DAI for addressing their own data access and
integration requirements within Grid environments now and in the near
future.
Background
The UK-based OGSA-DAI (Open Grid Service Architecture - Data Access
and Integration) project is developing middleware to allow:
» The exposure of data resources to Grids using web services.
» Application-specific data access and integration.
OGSA-DAI is already being used by a number of large projects within
the UK, the US and Asia to satisfy their data access and integration
requirements. In addition to this, the OGSA-DAI project is a member of
both the Globus Alliance and OMII UK - this collaboration enables the
seamless integration of OGSA-DAI into both the Globus Toolkit and the
OMII platform.
OGSA-DAI is currently available in two versions:
» OGSA-DAI WSRF 2.2 which is compliant with Globus 4.0.2.
» OGSA-DAI WSI 2.2 which is compliant with Axis 1.2.1, Axis 1.2RC3,
and OMII 2.3.3.
Architecture
OGSA-DAI uses a layered architecture to allow data resources to be
exposed onto a Grid via web services:
» Data resources sit outwith OGSA-DAI and hold application-specific
data:
-Relational databases (MySQL, PostgreSQL, IBM DB2, Oracle, Microsoft
SQL Server).
-XML databases (eXist).
-File systems (including text, binary, SwissProt and OMIM file
formats).
» Data resource accessors interact with data resources using standard
APIs such as JDBC or XMLDB.
» Data service resources are the core of OGSA-DAI. These manage:
-Access to a data resource via a data resource accessor.
-Execution of data-related activities by OGSA-DAI's activity
framework and enactment engine.
-Data caching and streaming of data to and from clients or to
third-parties.
-Creation, access and termination of sessions.
-Access to information about resources, activities and requests.
» Data services are web services. They are the access point for clients
wishing to interact with data service resources.
Extensibility
OGSA-DAI is designed to be highly-extensible:
» Developers can provide support for application-specific data
resources not officially supported by OGSA-DAI.
-This includes "virtual data resources" which integrate data from
other data resources (which may be accessed via remotely-located
data services).
» Developers can provide support for resource management including the
creation and destruction of application-specific persistent and
transient data service resources.
» Developers can develop and utilise their own application-specific
activities within OGSA-DAI.
» Developers can provide application-specific authorization at the
data service resource and activity level (in addition to the
service-level authorization supported by web services containers
hosting OGSA-DAI services and data-level authorization supported by
data resources).
Usage
OGSA-DAI can be deployed in a number of ways to provide access to
and manipulation of data. There are a selection of scenarios that the
OGSA-DAI project have analysed:
» Using OGSA-DAI behind an application-specific service.
» Accessing and integrating multiple distributed data resources.
» Federating data.
» Using OGSA-DAI to provide application-specific services.
» Handling BLOBs.
Further Information
For more information about OGSA-DAI please visit the OGSA-DAI website
at http://www.ogsadai.org.uk.
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