https://doi.org/10.1051/epjconf/202125104014
Design of a Resilient, High-Throughput, Persistent Storage System for the ATLAS Phase-II DAQ System
1 University of Liverpool, The Oliver Lodge, Oxford St, Liverpool L69 7ZE, United Kingdom
2 European Laboratory for Particle Physics (CERN), Geneva 23, CH-1211, Switzerland
3 Instituto de Ciencias de la Computación UBA-CONICET, Ciudad Universitaria, CABA, Argentina
4 Università degli Studi di Pavia and INFN, Via Agostino Bassi, 6, Pavia, Italy
* e-mail: adam.abed.abud@cern.ch
** e-mail: matias.alejandro.bonaventura@cern.ch;mbonaventura@dc.uba.ar
Published online: 23 August 2021
The ATLAS experiment will undergo a major upgrade to take advantage of the new conditions provided by the upgraded High-Luminosity LHC. The Trigger and Data Acquisition system (TDAQ) will record data at unprecedented rates: the detectors will be read out at 1 MHz generating around 5 TB/s of data. The Dataflow system (DF), component of TDAQ, introduces a novel design: readout data are buffered on persistent storage while the event filtering system analyses them to select 10000 events per second for a total recorded throughput of around 60 GB/s. This approach allows for decoupling the detector activity from the event selection process. New challenges then arise for DF: design and implement a distributed, reliable, persistent storage system supporting several TB/s of aggregated throughput while providing tens of PB of capacity. In this paper we first describe some of the challenges that DF is facing: data safety with persistent storage limitations, indexing of data at high-granularity in a highly-distributed system, and high-performance management of storage capacity. Then the ongoing R&D to address each of the them is presented and the performance achieved with a working prototype is shown.
© The Authors, published by EDP Sciences, 2021
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
