LHC Data Analysis Using NFSv4.1 (pNFS): A Detailed Evaluation

NFSv4.1 (pnfs) is a new industry standard which allows for access to data distributed on different file servers. The dCache storage system has implemented this protocol. The aim of this paper is to evaluate this implementation and compare it to traditional HEP protocols like dCap. We perform synthetic and simple ROOT tests as well as real analysis tests using the ATLAS HammerCloud framework and an analysis use case from CMS. The tests are done on a cluster comparable to a small analysis cluster. Our tests have shown that the dCache NFSv4.1 (pnfs) implementation is very stable and that analysis speed is at least comparable if not superior to dCap in general. In addition, our test have shown that no change to analysis were needed to make use of the new protocol.