International Conference on Computing in High Energy and Nuclear Physics, Date: 2007/09/02 - 2007/09/07, Location: Victoria, BC, Canada

Publication date: 2008-01
Volume: 119 Pages: 022005 -
ISSN: 1742-6588, 1742-6596
DOI: 10.1088/1742-6596/119/2/022005
Publisher: Institute of Physics Publishing Ltd.

Journal of Physics - Conference Series


Amorim, A
Lopes, L ; Pereira, P ; Simoes, J ; Soloviev, I ; Burckhart, D ; Von Der Schmitt, J ; Caprini, M ; Kolos, S


02 Physical Sciences, 09 Engineering


The access of the ATLAS Trigger and Data Acquisition (TDAQ) system to the ATLAS Conditions Databases sets strong reliability and performance requirements on the database storage and access infrastructures. Several applications were developed to support the integration of Conditions database access with the online services in TDAQ, including the interface to the Information Services (IS) and to the TDAQ Configuration Databases. The information storage requirements were the motivation for the ONline Asynchronous Interface to COOL (ONASIC) from the Information Service (IS) to LCG/COOL databases. ONASIC avoids the possible backpressure from Online Database servers by managing a local cache. In parallel, OKS2COOL was developed to store Configuration Databases into an Offline Database with history record. The DBStressor application was developed to test and stress the access to the Conditions database using the LCG/COOL interface while operating in an integrated way as a TDAQ application. The performance scaling of simultaneous Conditions database read accesses was studied in the context of the ATLAS High Level Trigger large computing farms. A large set of tests were performed involving up to 1000 computing nodes that simultaneously accessed the LCG central database server infrastructure at CERN.