2002 - cesnet

11.1.2 Version 2.0We concentrated our main activities on the complex reconstruction of thelogging service concept and implementation of new functions. The loggingservice is based upon the event-driven model, where individual componentssend information on particular events to a remote database and task states are(re)constructed accordingly.The basic logging service is asynchronous, i.e., neither timely delivery ofevents, nor their order is guaranteed. Nevertheless, this approach becomesinsufficient in situations where the logging service is used internally within theresource management system for transferring information, e.g., when recoveringthe status after a certain component collapsed. For this purpose, we haveextended the model with the support of the priority and synchronous eventlogging, within which a logging function call is not ended until the event transferto the (remote) database is confirmed.The most essential modification is the extended support of types of loggedevents that will also allow logging of so-called user events, i.e., events generateddirectly by a user and/or the application itself. This support virtually requireda complete reconstruction of the existing implementation, which supports easyintegration of new event types in version 2.0.For version 2.0, we also changed the event processing concept and implementationof the so-called state automaton. The state automaton in version 2.0 nowprocesses all incoming events and stores the resulting state accompanied witha timestamp to the database. We expanded the state cache concept, in whichstates of events that are most frequently requested by users are stored. The fullversion 2.0 functionality (including C and C++ API) is described in appropriatedocuments of the DataGrid project.In addition to our other activities, we started to deal also with the issue of apermanent logging service, which will be capable of storing information abouttasks for very long time periods (years). The first version of the appropriatedocument is currently subject to our internal review procedure.11.1.3 R-GMA and Logging ServiceR-GMA, i.e., the Relational Grid Monitoring Architecture, represents a generalconcept of working with monitoring information within the DataGrid project.R-GMA should provide an infrastructure that will be used to collect monitoringinformation and make them available. Basically, the monitoring information includesinformation on task states as well.142 High-speed National Research Network and its New Applications 2002