[en] In the framework of a distributed computing environment, such as WLCG, monitoring has a key role in order to keep under control activities going on in sites located in different countries and involving people based in many different sites. To be able to cope with such a large scale heterogeneous infrastructure, it is necessary to have monitoring tools providing a complete and reliable view of the overall performance of the sites. Moreover, the structure of a monitoring system critically depends on the object to monitor and on the users it is addressed to. In this article we will describe two different monitoring systems both aimed to monitor activities and services provided in the WLCG framework, but designed in order to meet the requirements of different users: Site Status Board has an overall view of the services available in all the sites supporting an experiment, whereas Siteview provides a complete view of all the activities going on at a site, for all the experiments supported by the site.

[en] Job processing and data transfer are the main computing activities on the WLCG infrastructure. Reliable monitoring of the job processing on the WLCG scope is a complicated task due to the complexity of the infrastructure itself and the diversity of the currently used job submission methods. The paper will describe current status and the new strategy for the job monitoring on the WLCG scope, covering primary information sources, job status changes publishing, transport mechanism and visualization.