The ALICE online-offline framework for the extraction of conditions data

A Large Ion Collider Experiment (ALICE) is the dedicated heavy-ion experiment at the CERN LHC and will take data with a bandwidth of up to 1.25 GB/s. It consists of 18 subdetectors that interact with five online systems (CTP, DAQ, DCS, ECS, and HLT). Data recorded is read out by DAQ in a raw data stream produced by the subdetectors. In addition the subdetectors produce conditions data derived from the raw data, i.e. calibration and alignment information, which have to be available from the beginning of the reconstruction and therefore cannot be included in the raw data. The extraction of the conditions data is steered by a system called Shuttle. It provides the link between data produced by the subdetectors in the online systems and a dedicated procedure per subdetector, called preprocessor, that runs in the Shuttle system. The preprocessor performs merging, consolidation, and reformatting of the data. Finally, it stores the data in the Grid Offline Conditions DataBase (OCDB) so that they are available for the Offline reconstruction. The reconstruction of a given run is initiated automatically once the raw data is successfully exported to the Grid storage and the run has been processed in the Shuttle framework. These proceedings introduce the Shuttle system. The performance of the system during the ALICE cosmics commissioning and LHC startup is described.