Off-Site Computing Farm for the LHCb High Level Trigger

The LHCb High Level Trigger (HLT) farm consists of about 1500 dual-socket servers, which are housed in the underground server room. Due to constraints of the power supply and cooling systems, it is difficult to install more servers in this room in the future. An off-site farm is a solution to enlarge the computing capacity. In this paper, we will demonstrate the concept of LHCb off-site HLT farm extension into the CERN computing center. Furthermore, the performance of the key technologies have been tested in the lab.