The DESY Production Grid ======================== Andreas Gellrich, DESY (Speaker: Patrick Fuhrmann, DESY) DESY is one of the world-wide leading centers for research with particle accelerators and a center for research with synchrotron light. The hadron- electron collider HERA houses four experiments which are taking data and will be operated until 2007. The H1 and ZEUS collaborations at HERA-II have started to exploit the Grid for their growing demand for Monte Carlo events after the update of the collider. DESY participates in a number of national and international Grid projects. Among them are the German e-science initiative D-GRID, the EU-project Enabling Grid for E-sciencE (EGEE), and the International Lattice Data Grid (ILDG). In addition activities have started to exchange simulation data within the International Linear Collider Community (ILC). The Grid Infrastructure at DESY is based on the so-called DESY Production Grid which make use of the LCG-2 middleware and is operated in the LCG TestZone. It is set up to provide generic Grid services for all Grid activities at DESY. Therefore the DESY Production Grid incorporates all necessary elements of a complete and independent Grid. This includes a Resource Broker, catalog services for replica and meta data management, and a dCache-based Storage Element which provides access to the entire DESY data space of 0.5 PB to the Grid. In the contribution to HEPiX we will describe the DESY Production Grid in the context of the DESY Grid activities and present operation experiences.