R-GMA: First results after deployment
Rob Byrom, Brian Coghlan, Andrew W Cooke, Roney Cordenonsi, Linda Cornwall, Ari Datta, Abdeslem Djaoui, Laurence Field, Steve Fisher, Steve Hicks, Stuart Kenny, James Magowan, Werner Nutt, David O'Callaghan, Manfred Oevers, Norbert Podhorszki, John Ryan, Manish Soni, Paul Taylor, Antony J. Wilson, Xiaomei Zhu
Abstract
We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the European DataGrid Project as an Grid Information and Monitoring System. Is is based on the GMA from GGF, which is a simple Consumer-Producer model. The special strength of this implementation comes from the power of the relational model. We offer a global view of the information as if each VO had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers to do the job. We are able to invoke MDS info-provider scripts and publish the resulting information via R-GMA in addition to having some of our own sensors. APIs are available which allow the user to deploy monitoring and information services for any application that may be needed in the future. We have used it both for information about the grid (primarily to find what services are available at any one time) and for application monitoring. R-GMA has been deployed in Grid testbeds, we describe the results and experiences of this deployment.