CERN Accélérateur de science

ATLAS Note
Report number	ATL-DAQ-PROC-2018-043
Title	Highly extensible modular system for online monitoring of the ATLAS experiment
Author(s)	Kolos, Serguei (University of California, Irvine)
Corporate Author(s)	The ATLAS collaboration
Collaboration	ATLAS Collaboration
Publication	2018
Imprint	03 Dec 2018
Number of pages	8
In:	23rd International Conference on Computing in High Energy and Nuclear Physics, CHEP 2018, Sofia, Bulgaria, 9 - 13 Jul 2018
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	Online Monitoring ; Histogram ; Data Quality
Abstract	Unprecedented size and complexity of the ATLAS experiment required adoption of the new approach for online monitoring system development as many requirements for this system were not known in advance due to the innovative nature of the project. The ATLAS online monitoring facility has been designed as a modular system consisting of a number of independent components, which can interact with one another via a set of well-defined interfaces. The system has been developed using open source software and is based on the two in-house developed highly scalable distributed services for message passing and information exchange, which can deal with information of arbitrary types. The other monitoring components use these services to implement high-level facilities, like for example Monitoring Data Archiving and Data Quality Assessment, as well as end user interfaces like the Data Quality and Online Histogramming displays. This paper describes the online monitoring system design and evolution showing how the chosen approach allowed the system to be gradually extended by adding more high level tools and frameworks as requirements evolved.