  The Daya Bay Reactor Neutrino Experiment started running on September 23,
2011. The offline computing environment, consisting of 11 servers at Daya Bay,
was built to process onsite data. With current computing ability, onsite data
processing is running smoothly. The Performance Quality Monitoring system (PQM)
has been developed to monitor the detector performance and data quality. Its
main feature is the ability to efficiently process multi-data-stream from three
experimental halls. The PQM processes raw data files from the Daya Bay data
acquisition system, generates and publishes histograms via a graphical web
interface by executing the user-defined algorithm modules, and saves the
histograms for permanent storage. The fact that the whole process takes only
around 40 minutes makes it valuable for the shift crew to monitor the running
status of all the sub-detectors and the data quality.
