CERN Accelerating science

ATLAS Note
Report number	ATL-SOFT-PROC-2020-016
Title	Improvements in utilisation of the Czech national HPC center
Related title	Improvements in utilisation of the Czech national HPC center by ATLAS distributed computing
Author(s)	Svatos, Michal (Institute of Physics of the Czech Academy of Sciences) ; Chudoba, Jiri (Institute of Physics of the Czech Academy of Sciences) ; Vokac, Petr (Czech Technical University in Prague)
Collaboration	ATLAS Collaboration
Publication	2020
Imprint	27 Feb 2020
Number of pages	8
In:	EPJ Web Conf. 245 (2020) 09010
In:	24th International Conference on Computing in High Energy and Nuclear Physics, Adelaide, Australia, 4 - 8 Nov 2019, pp.09010
DOI	10.1051/epjconf/202024509010
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	computing ; HPC
Abstract	The ATLAS distributed computing is allowed to opportunistically use resources of the Czech national HPC center IT4Innovations in Ostrava. The jobs are submitted via an ARC Compute Element (ARC-CE) installed at the grid site in Prague. Scripts and input files are shared between the ARC-CE and shared file system located at the HPC via sshfs. This basic submission system has worked there since the end of 2017. Several improvements were made to increase amount of resource that ATLAS can use. The most significant one was the migration of the submission system to enable pre-emptable jobs, as the HPC management made the decision to use pre-emption on opportunistic jobs. Another improvement of the submission system is related to the sshfs connection which seemed to be a limiting factor of the system. Now, the submission system consists of several ARC-CE machines. Also, various parameters of sshfs were tested in an attempt to increase throughput. As a result of the improvements, the utilisation of the Czech national HPC center by the ATLAS distributed computing increased.
Related document	Slides ATL-SOFT-SLIDE-2019-800

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