First Operational Experience With a High-Energy Physics Run Control System Based on Web Technologies

Run control systems of modern high-energy particle physics experiments have requirements similar to those of today's Internet applications. The Compact Muon Solenoid (CMS) collaboration at CERN's Large Hadron Collider (LHC) therefore decided to build the run control system for its detector based on web technologies. The system is composed of Java Web Applications distributed over a set of Apache Tomcat servlet containers that connect to a database back-end. Users interact with the system through a web browser. The present paper reports on the successful scaling of the system from a small test setup to the production data acquisition system that comprises around 10.000 applications running on a cluster of about 1600 hosts. We report on operational aspects during the first phase of operation with colliding beams including performance, stability, integration with the CMS Detector Control System and tools to guide the operator.