D0 Data Handling Operational Experience

We report on the production experience of the DØ experiment at the Fermilab Tevatron, using the SAM data handling system with a variety of computing hardware configurations, batch systems, and mass storage strategies. We have stored more than 300 TB of data in the Fermilab Enstore mass storage system. We deliver data through this system at an average rate of more than 2 TB/day to analysis programs, with a substantial multiplication factor in the consumed data through intelligent cache management. We handle more than 1.7 Million files in this system and provide data delivery to user jobs at Fermilab on four types of systems: a reconstruction farm, a large SMP system, a Linux batch cluster, and a Linux desktop cluster. In addition, we import simulation data generated at 6 sites worldwide, and deliver data to jobs at many more sites. We describe the scope of the data handling deployment worldwide, the operational experience with this system, and the feedback of that experience.