Grid Information System

The Grid Information System provides detailed information about grid services. The Grid Information System system has a hierarchical structure of three levels. The fundamental building block used in this hierarchy is the Berkley Database Information Index (BDII). Although the BDII has additional complexity, it can be visualized as an LDAP database. The resource level or core BDII is usually co-located with the grid service and provides information about that service. Each grid site runs a site level BDII. This aggregates the information from all the resource level BDIIs running at that site. The top level BDII aggregates all the information from all the site level BDIIs and hence contains information about all grid services. There are multiple instances of the top level BDII in order to provide a fault tolerant, load balanced service. The information system clients query a top level BDII to find the information that they require.