Distributed Data Management in CMS

Within 5 years CMS expects to be managing many tens of petabytes of data in tens of sites around the world. This represents more than order of magnitude increase in data volume over existing HEP experiments. This presentation will describe the underlying concepts and architecture of the CMS model for distributed data management, including connections to the new CMS Event Data Model. The technical descriptions of the main data management components for dataset bookkeeping, data location and file access will be presented. In addition we will present our first experience in using the system in preparation for a CMS data challenge in summer 2006.