The Open Compute Project, OCP, was launched by Facebook in 2011 with the objective of building efficient computing infrastructures at lowest possible cost. Specifications and design documents for Open Compute systems are released under open licenses following the model traditionally associated with open source software projects. In 2014 we presented our plans for a public procurement activity for a small-size Open Compute hardware installation aimed at assessing the maturity of OCP market and whether it could be identified as a possible competitor of "traditional" hardware (Open Compute at CERN, HEPiX Spring 2014). We have finally deployed in September 2015 six Open Compute racks populated with CPU servers and storage enclosures in CERN's Meyrin datacentre. We were presented with interesting challenges during all phases of the project and at all levels of the stack, from the power distribution to hardware monitoring. I will outline some of the hurdles we had to overcome and the lessons we have learnt along the way, together with the results obtained during the evaluation of the systems.