Operation and performance of the CMS tracker

The CMS silicon tracker is the largest silicon detector ever built. It consists of an inner pixel detector, with 66 million readout channels, and an outer 200 m$^{2}$ silicon strip detector with 10 million channels. The successful operation of this detector during the first three years of LHC running with proton-proton and heavy ion collisions is discussed. Results include operational challenges encountered during data taking that influenced the active fraction and readout efficiency of the detectors. Details are given on the performance at high occupancy with respect to local observables, such as signal-to-noise ratio and hit reconstruction efficiency, and on radiation effects with respect to the evolution of power consumption, sensor bias, readout thresholds and leakage current.