ALICE analysis model Pablo Saiz 10182021 Pablo Saiz

ALICE analysis model Pablo Saiz 10/18/2021 Pablo Saiz 1

Computing model Similar for AA

aa pp

Analysis software: Ali. ROOT • Built on top of ROOT • Used for simulation, reconstruction and analysis • Can be run: locally on PROOF clusters on the GRID (Ali. En) 10/18/2021 Pablo Saiz 7

Ali. En • All components needed for GRID – File & Medatada catalogue (quotas, collections, envelopes) – Job execution model (pull model, Job. Agent, priorities, splitting, merging, sending job to data …) – SE discovery – File Transfer mechanism – Software package installation – Interfaces to other middleware implementations • Central services and site services (vobox) • Used by ALICE, PANDA and CBM • End users do not need ‘topology information’ – Ali. En decides site, CE, SE… 10/18/2021 Pablo Saiz 8

Ali. En Job Execution Site A CE CM Mon. ALISA Packman SRM File catalogue LFN GUID Meta data Job Manager Task. Queue Job Broker Jobs CE JA SRM Packman Mon. ALISA Splitting Expired Zombies Central services Site services Non Ali. En Services 10/18/2021 Priorities Merging xrootd CM Site B Job optimizers Pablo Saiz 9

How SE discovery works • Select closest working SE of a Qo. S: Client I’m in ‘Madrid’ Give me SEs! Authen Optimizer Try: CCIN 2 P 3, CNAF, Kosice File Catalogue SERank Similar process for read (limited to SE having the file) Can select number of SE, Qo. S, particular user, avoid SE. . . DEFAULT ARGUMENTS SHOULD BE USED WHENEVER POSSIBLE 10/18/2021 Pablo Saiz 10

Simplest analysis • alien login – Submit ‘Executable =“/bin/date”’ • Input and output in the Ali. En file catalogue • Ali. En chooses execution site and output SE • Follow the status of the job with Mon. ALISA – Or with alien tools – Or web interface 10/18/2021 Pablo Saiz 11

Analysis example What to run Data to analyze notification Where to register the output Added by Ali. En 10/18/2021 Pablo Saiz 12

Analysis train

Proof On Demand Untitled

User support • Through email list: – alice-project-analysis-task-force@cern. ch – Answered by users and ALICE offline • Site administrators: – alice-lcg-task-force@cern. ch – Answered by users, ALICE offline, IT/ES 10/18/2021 Pablo Saiz 16

Summary • Achievements • Challenges – Central File Catalogue – Single Task. Queue – Common data access protocol – Analysis train – SE discovery – Security envelopes 10/18/2021 Pablo Saiz – Interactive analysis – Proof On Demand – Remote data access o Paradigm change? – Single Point of Failures (? ) – Lack of resources – Cleanup of SE (? ) – Orphan files 17

Links • • • ALICE COMPUTING MODEL: http: //indico. cern. ch/get. File. py/access? contrib. Id=43&session. Id=11&res. Id=0&mat erial. Id=slides&conf. Id=33846 ANALYSIS FRAMEWORK: http: //indico. cern. ch/get. File. py/access? contrib. Id=174&session. Id=4&res. Id=0&mat erial. Id=slides&conf. Id=34666 ALICE offline bible: http: //aliweb. cern. ch/Offline/Ali. Root/Manual. html Ali. En: http: //indico. cern. ch/get. File. py/access? contrib. Id=56&session. Id=9&res. Id=1&mate rial. Id=slides&conf. Id=111325 Xrootd: http: //indico. cern. ch/get. File. py/access? contrib. Id=57&session. Id=9&res. Id=1&mate rial. Id=slides&conf. Id=97355 http: //indico. cern. ch/get. File. py/access? contrib. Id=8&session. Id=2&res. Id=1&materi al. Id=slides&conf. Id=94434 Po. D: http: //indico. cern. ch/get. File. py/access? contrib. Id=52&session. Id=6&res. Id=0&mate rial. Id=slides&conf. Id=111325 10/18/2021 Pablo Saiz 18