LHCb High Level Trigger in remote IT datacentre

In 2017 the CERN IT department and the major LHC experiments reviewed the possibility to build a common High Level Trigger facility, to share costs and for a more efficient utilization of computing resources. This paper describes a Proof-of-Concept built by the CERN IT-CS group and the LHCb online and offline teams to demonstrate the feasibility of the proposal: the dedicated, high speed connection between the LHCb detector and the IT data-centre, the setup of the servers and how they were used for offline simulation and online data taking, the different technologies considered and used, the challenges encountered and how they were tackled. The Proof of Concept exceed expectations and the remote servers were used for real data taking for more than two months during the summer 2018.