Since several years the European Synchrotron Radiation Facility [ESRF] serves 40 beamlines with a stable photon beam during 5600 h per year and a reliability of 97%. The vacuum system, as one of the subsystems, appears to pay an crucial role in the operation of such a facility. A review is given about the main difficulties experienced and the actions taken to overcome them. Aspects of instrumentation, interlocks, machine vacuum parts and control will be discussed.