A design study for the upgraded ALICE O(2) computing facility

An upgrade of the ALICE detector is currently prepared for the Run 3 period of the Large Hadron Collider (LHC) at CERN starting in 2020. The physics topics under study by ALICE during this period will require the inspection of all collisions at a rate of 50 kHz for minimum bias Pb-Pb and 200 kHz for pp and p-Pb collisions in order to extract physics signals embedded into a large background.The upgraded ALICE detector will produce more than 1 TByte/s of data. Both collision and data rate impose new challenges onto the detector readout and compute system. Some detectors will not use a triggered readout, which will require a continuous processing of the detector data. The challenging requirements will be met by a combined online and offline facility developed and managed by the ALICE O(2) project. The combined facility will accommodate the necessary substantial increase of data taking rate.In this paper we present first results of a prototype with estimates for scalability and feasibility for a full scale system.