1-2 March 2006 P. Capiluppi INFN Tier1 for the LHC Experiments: ALICE, ATLAS, CMS, LHCb

2 P. Capiluppi 1-2 March 2006 LHC: role of a Tier1 (short remind) u Custodial of a fraction (1/#Tier1s) of Raw & Reconstructed (ESD aka RECO aka DST) Data u Full set of AODs u Reprocessing of data (re-reconstruction) u Skimming and selection of data (Large analysis jobs by Physics Groups) {ALICE, ATLAS, CMS} u User analyses {LHCb} u Distribution of data to the Tier2s u Many services needed for that (SLA):  Accounting (fair share of resources)  Permanent storage  Data access, location and distribution  User accesses  Job tracking and monitoring  Availability 24x7, … etc.

3 P. Capiluppi 1-2 March 2006 The LHC (shared) Tier1-CNAF

4 P. Capiluppi 1-2 March 2006 Usage so far of the Tier1-CNAF by the Italian LHC community u Simulation & reconstruction u Data & Computing Challenges u WLCG Service challenges u Analysis of simulated data u Custodial for many produced data (simulated and real, like test-beams data, cosmic, etc.) u Test of many “new” functionalities  Both “Grid-like” and “Experiment-specific” u LHC is (still) not running, therefore  LHC Experiments activities have spikes  The role (and use) of the Tier1 is (still) not that of the Computing TDRs

5 P. Capiluppi 1-2 March 2006 Use of Tier1 (Grid only) ATLAS LHCb CMS ALICE Nov 2005 Total CPU Time LHC Jobs/day: Dec05-Feb06

6 P. Capiluppi 1-2 March 2006 Analysis: CMS-CRAB Monitor Submitted jobs Submitted from Destination of jobs

7 P. Capiluppi 1-2 March 2006 ALICE Simulation jobs at CNAF Tier1 Pb-Pb events JAN-27 FEB-10 Done jobs

8 P. Capiluppi 1-2 March 2006 WLCG SC3 rates CNAF

9 P. Capiluppi 1-2 March 2006 Services: really “a number” of…  CEs, SEs, RBs, UIs, VOMS, Information Systems, Catalogs, etc. And…  Mass Storage system, disk file systems, LAN configuration, data-base services, Accounting, Monitoring, compilers, libraries, experiments’ software and libraries, shared caches, etc. u Most of them are there, however u Integration of WLCG and specific needs of the experiments might be a problem u The INFN Tier1 is part of WLCG, INFN-Grid, EGEE programs: mostly integrated, but… u Castor(2) is quite new (and in evolution), but is a key element of the Tier1: support by and collaboration with CERN? u File transfer from/to the Tier0, the Tier1s, the Tier2s is still largely untested (SC4) u Publication of data (files, or better “datasets”) needs a strong interaction with experiments for the implementation at the Tier1

10 P. Capiluppi 1-2 March 2006 Services: really “a number” of… Storage Storage Storage (and CPUs) And in addition: u WLCG Service Challenge 4?  “Production” vs “Challenge”  Duplication of effort? u Partitioning the Tier1?  For different scopes, different experiments and also different needs within an experiment?  Is it needed, desirable, possible? And if yes, how?

11 P. Capiluppi 1-2 March 2006 Supporting the Experiments  Single shared Farm  Same File system  Experiment dedicated Storage Elements  Common services (WLCG) u Too many Experiments?  Integration with WLCG is enough? And the non-WLCG Experiments? è Also, compatibility with other Experiments Tier1s  Problem solving and resources-competition u Specific services needed by Experiments (maybe temporally)  How to manage? Procedures? u User support  Accounts (on UIs)  Interactive access (development machines)  Dedicated queues for particular purposes  Etc. Good, but

12 P. Capiluppi 1-2 March 2006 And … Experiments supporting Tier1 u LHC Experiments personnel is actively working with the Tier1 personnel on:  Disk storage file-systems performances testing {LHCb, CMS, ALICE, …} è GPFS, dCache, Parallel File Systems, …  File Transfers tools {CMS,ALICE, …} è FTS, …  Catalogs { ALICE, ATLAS, CMS,…} è Data-base services usage and implementation (Oracle, MySQL, Squidd, Frontier, …)  VO-Boxes {ALICE, ATLAS, CMS, …} è Harmonization with the common services  WLCG Service Challenges {CMS, ALICE, ATLAS, …} è Service implementation and running  WMS (Workload Management System) {ATLAS, ALICE, CMS, …} è Feedback on performances and setup

13 P. Capiluppi 1-2 March 2006 WMS performances tests: ATLAS/LCG/EGEE Task Force gLiteLCG (sec/job)Submission Match- making OverallSubmission Match- making Overall Simple hello world ~ Simple hello world with CE requirement ~ LS with 48 KB inputsandbox (partially shared) ~ u gLite  Observable effect comes from the number of matched CEs  The inputsandbox effect on submission still not be fully understood with the data in the table u LCG  Match-making takes place right after submission  No observable effect from the number of matched CEs  Submission of job with inputsandbox is about 2 times slower than simple hello world job

14 P. Capiluppi 1-2 March 2006 What we would like to have now … and is (still) missing u Storage accounting and quotas  For the use of the Experiments (runs or datasets, not files) u Job priority (Tier1 has to guarantee agreed sharing) u Catalogs  Data-bases for data-access: common and experiments specific u Experiments support: too few people  <~ one person per experiment (LHC) u Transparent access to heterogeneous hardware u Link and co-ordination with Experiments is a KEY ISSUE  Operations  Planning  Clear interfaces and contacts (for every issue)  Testing & integration of Experiments specific software è How, when and if possible (decision taking process) Both functions urgently needed

15 P. Capiluppi 1-2 March 2006 Conclusions A Tier1 already working for the LHC Experiments  With reasonable satisfaction  We got a lot of support, both common and specific, by very technically competent personnel  However we are very worried of  The Tier1 is largely understaffed  and also very few senior personnel for management Ü consequently a lack of personnel dedicated to Experiments support  However, experiments’ people from outside sites is already supporting Tier1  Organization of the link/interaction with experiments  Must be improved  To Guarantee the experiments commitments and the Tier1 running  in addition  Few (many?) other areas that need urgent investments  Storage access and use  User interaction with the Center  Procedures for interventions (emergency and routine)  Means for notifications of events (of any kind, not only for Italy) Last but not the least: Hardware procurement