On the potential use of remote computing farms in the ATLAS TDAQ system

The ATLAS experiment at CERN will require a large amount of computing resources for the online analysis system. The software and communication protocols in the ATLAS online analysis system are optimized for a cluster environment. We setup a geographically distributed testbed to evaluate the implications of integrating remote computing resources in this environment. This paper reports on the integration scenarios and analyzes the achieved performance. We highlight limitations in the communication protocols and suggest solutions for solving them. A proposal for employing grid-enabled resources to allow for on-demand expansion of the computing capabilities is presented at the end of the paper