Kukushev, A.

Schwarz, K.

GSI Repository

Improved operation for the ALICE Tier2 Centre at GSIK. Schwarz, A. Kukushev11GSI, Darmstadt, GermanyThis article describes the improvements implemented in2014 to increase the reliability and performance of the AL-ICE Tier2 Computing Centre at GSI.ALICE tier2 centre at GSI and ALICE Gridin GermanyThe ALICE tier2 centre and the National Analysis Fa-cility at GSI provide a computing infrastructure for ALICEGrid and for the local usage of the German ALICE groups.The storage resources pledged to the global ALICE com-munity (550 TB) are provided via a Grid Storage Elementwhich consists of an xrootd [1] daemon running on top ofthe Lustre file system.In this contribution an enabling technology is describedwhich gives the possibility to include local HPC resourcesinto a distributed computing environment for ALICE andFAIR. A prototype has been implemented which will beoperated in production mode for the ALICE tier2 centre atGSI. The work done in this context is also an importantcontribution to the Data Life Cycle Lab ”Structure of Mat-ter/FAIR” within the portfolio project ”Large Scale DataManagement and Analysis (LSDMA)” [2].The new storage infrastructure as described in this arti-cle can also be used by Grid jobs in the firewall protectedenvironment of the GSI HPC cluster.Figure 1: GSI storage setupThe main elements are the xrootd redirector as well asthe xrootd forward proxy server. The redirector is using thesplit directive of xrootd and redirects external clients to theexternal interface of the GSI storage element and internalclients to the internal interface which is directly connectedto the local Infiniband Cluster. The xrootd forward proxyserver provides the possibility to Grid jobs running insidethe protected HPC environment to read input data from ex-ternal data sources using the proxy interface. Writing to ex-ternal storage elements is possible via the same technique.The setup is shown in fig. 1.Throughout the year GSI participates in centrally man-aged ALICE Grid productions and data analysis activities,but also analysis jobs of individual users are running onthe ALICE tier2 centre. The overall job share of success-fully computed jobs in 2014 contributed by the GermanGrid sites, the GSI tier2 centre and ForschungszentrumKarlsruhe (ALICE tier1 centre) has been 10% of all AL-ICE Grid jobs worldwide. This corresponds well with thepledged CPU resources for 2014: 7000 HEP-SPEC06 forGSI tier2 (4% of the global T2 requirements) and 30000HEP-SPEC06 for FZK (27% of the global T1 require-ments)High Level Service Monitoring for the GSIALICE Tier2 centreWithin a Bachelor Thesis supervised in cooperation withHochschule Darmstadt a High Level Service MonitoringTool for the GSI ALICE Tier2 centre has been developed.After identifying the Key Performance Indicators which arerelevant for characterizing the smooth operation of the AL-ICE Tier2 centre a High Level Service Monitoring tool hasbeen implemented in JavaScript using Node.js, the Node.jsframework Express.js and Jade for HTML templates. De-pending on the functionality red, green, or yellow lightsshow the current status of the ALICE Tier2 Centre and helpin providing a reliable service. A screenshot can be seen infig. 2Figure 2: KPI ALICE Monitoring GSI Tier2References[1] http://xrootd.org/[2] http://www.helmholtz-lsdma.de/GSI SCIENTIFIC REPORT 2014 INFRASTRUCTURE-IT-12DOI:10.15120/GR-2015-1-INFRASTRUCTURE-IT-12 381

Improved operation for the ALICE Tier2 Centre at GSI

http://repository.gsi.de/record/184103/files/INFRASTRUCTURE-IT-12.pdf

Improved operation for the ALICE Tier2 Centre at GSI

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