The ATLAS experiment is one of the four major experiments of the CERN Large Hadron Collider (LHC). ATLAS is a general-purpose physics experiment run by an international collaboration of scientists, with the aim of fully exploiting the potential of the LHC to answer fundamental questions such as discovering the fundamental building blocks of matter or the fundamental forces of nature. One of the most prominent activities of ATLAS is its involvement along with the CMS in the discovery of the Higgs boson.

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Switzerland provides computational and storage resources to ATLAS. However, ATLAS faces increasing computational demands in order to fully exploit the scientific data produced. As the complexity and size of data increases, more powerful computational infrastructure will be required to process and analyse it. One potential approach for dealing with this is the use of cloud computing resources, which have become increasingly popular in recent years.

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In this support project led by S3IT and in cooperation with the physics department at the University of Bern, different cloud infrastructures, including the academic SWITCHengines platform, were tested for the processing of ATLAS data. The ElastiCluster software from the University of Zurich was used to set up and implement 320 SWITCHengines cores in about an hour to process ATLAS data. The performance of the infrastructure in continuous operation was then recorded for several months.

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A number of conclusions can be drawn from this support project in regards to the feasibility of using SWITCHengines. Firstly, that there is a low setup time, and it is possible to quickly set up and implement a medium sized cluster of 1000 virtual CPU cores in less than a day. Secondly, over the course of several months, the uptime on SWITCHengines was close to 100%. In addition, maintenance on the user side was almost non-existent, which compares very favourably to the operation of own hardware where this certainly would not have been the case. Thirdly, that the cost of SWITCHengines is competitive with commercial cloud providers. As such, this support project suggests that cloud infrastructure, and in particular SWITCHengines, is a feasible and cost-efficient computing resource for ATLAS.