The data-acquisition (DAQ) system of the CMS experiment at the LHC performs the read-out and assembly of events accepted by the first level hardware trigger. Assembled events are made available to the high-level trigger (HLT) which selects interesting events for offline storage and analysis. The system is designed to handle a maximum input rate of 100 kHz and an aggregated throughput of 100 GB/s originating from approximately 500 sources. An overview of the architecture and design of the hardware and software of the DAQ system is given. We report on the performance and operational experience from the 2010 and ongoing 2011 collision runs for pp and heavy-ion operation. Furthermore, we will discuss the near and medium term future of the DAQ system in order to address extension of the HLT capability, maintenance issues, integration of sub-detectors with new back-end electronics and operation for LHC luminosity upgrades.