ATLAS off-Grid sites (Tier 3) monitoring. From local fabric monitoring to global overview of the VO computing activities

The ATLAS Distributed Computing activities have so far concentrated in the "central" part of the experiment computing system, namely the first 3 tiers (the CERN Tier0, 10 Tier1 centers and over 60 Tier2 sites). Many ATLAS Institutes and National Communities have deployed (or intend to) deploy Tier-3 facilities. Tier-3 centers consist of non-pledged resources, which are usually dedicated to data analysis tasks by the geographically close or local scientific groups, and which usually comprise a range of architectures without Grid middleware. Therefore a substantial part of the ATLAS monitoring tools which make use of Grid middleware, cannot be used for a large fraction of Tier3 sites. The presentation will describe the T3mon project, which aims to develop a software suite for monitoring the Tier3 sites, both from the perspective of the local site administrator and that of the ATLAS VO, thereby enabling the global view of the contribution from Tier3 sites to the ATLAS computing activities. Special attention in presentation will be paid generic monitoring solutions for PROOF and xrootd, covering monitoring components which collect, store and visualise monitoring data. One of the popular solutions for local data analysis is the PROOF-based computing facility with a simple storage system based on xrootd protocol. Monitoring of user activities at the PROOF-based computing facility as well as data access and data movement with xrootd is useful, both on the local and global VO level. The proposed PROOF and xrootd monitoring systems can be deployed as a part of the T3mon monitoring suite or separately as standalone components and can easily be integrated in the global VO tools for monitoring data movement, data access or job processing.