0522514 - FZÚ 2020 RIV FR eng C - Conference Paper (international conference)
Svatoš, Michal - De Salvo, A. - Dewhurst, A. - Vamvakopoulos, E. - Bahilo Lozano, J. - Ozturk, N. - Sánchez, J. - Dykstra, D.
Understanding the evolution of conditions data access through Frontier for the ATLAS Experiment.
EPJ Web of Conferences. Vol. 214. les Ulis: EDP Sciences, 2019 - (Forti, A.; Betev, L.; Litmaath, M.; Smirnova, O.; Hristov, P.), s. 1-8, č. článku 03020. ISSN 2100-014X.
[International Conference on Computing in High Energy and Nuclear Physics (CHEP 2018) /23./. Sofia (BG), 09.07.2018-13.07.2018]
R&D Projects: GA MŠMT LM2015058; GA MŠMT EF16_013/0001404
Grant - others:OP VVV - CERN-C(XE) CZ.02.1.01/0.0/0.0/16_013/0001404
Institutional support: RVO:68378271
Keywords : ATLAS * LHC Run 2 * Squid * experiment
OECD category: Automation and control systems
DOI: https://doi.org/10.1051/epjconf/201921403020

All ATLAS computing sites use Squid web proxies to cache the data, greatly reducing the load on the Frontier servers and the databases. One feature of the Frontier client is that in the event of failure, it retries with different services. While this allows transient errors and scheduled maintenance to happen transparently, it does open the system up to cascading failures if the load is high enough. Throughout LHC Run 2 there has been an ever increasing demand on the Frontier service. There have been multiple incidents where parts of the service failed due to high load. A significant improvement in the monitoring of the Frontier service was required. The monitoring was needed to identify both problematic tasks, which could then be killed or throttled, and to identify failing site services as the consequence of a cascading failure is much higher.
Permanent Link: http://hdl.handle.net/11104/0306994