efi.uchicago.edu ci.uchicago.edu FAX Dress Rehearsal Status Report Ilija Vukotic on behalf of the atlas-adc-federated-xrootd working group Computation and Enrico Fermi Institutes University of Chicago Software & Computing Workshop March 13, 2013

efi.uchicago.edu ci.uchicago.edu 2 All the slides are made by Rob Gardner, I just updated them. He can’t be here due to the OSG All Hands meeting.

efi.uchicago.edu ci.uchicago.edu 3 Data federation goals Create a common ATLAS namespace across all storage sites, accessible from anywhere Make easy to use, homogeneous access to data Identified initial use cases – Failover from stage-in problems with local storage – Gain access to more CPUs using WAN direct read access o Allow brokering to Tier 2s with partial datasets o Opportunistic resources without local ATLAS storage – Use as caching mechanism at sites to reduce local data management tasks o Eliminate cataloging, consistency checking, deletion services WAN data access group formed in ATLAS to determine use cases & requirements on infrastructure

efi.uchicago.edu ci.uchicago.edu 4 Implications for Production & Analysis Behind the scenes in the Panda + Pilot systems: – Recover from stage-in to local disk failures – This is in production at a few sites Development coming to allow advanced brokering which includes network performance – Would mean jobs no longer require dataset to be complete at a site – Allows “diskless” compute sites Ability to use non-WLCG resources – “Off-grid” analysis clusters – Opportunistic resources – Cloud resources

efi.uchicago.edu ci.uchicago.edu 5 FDR testing elements Starting week of January 21, we’ve been following a bottoms- up approach which builds stability in lower layers At-large users HammerCloud & WAN-FDR jobs (programmatic) HammerCloud & WAN-FDR jobs (programmatic) Network cost matrix (continuous) Basic functionality (continuous) Complexity

efi.uchicago.edu ci.uchicago.edu 6 Site Metrics “Connectivity” – copy and read test matrices HC runs with modest job numbers – Stage-in & direct read – Local, nearby, far-away Load tests – For well functioning sites only – Graduated tests 50, 100, 200 jobs vs. various # files – Will notify the site and/or list when these are launched Results – Simple job efficiency – Wallclock, # files, CPU %, event rate,

efi.uchicago.edu ci.uchicago.edu 7 Probes, integrated with AGIS Direct xrdcp copy of test files Copy using regional redirector At start of the FDR 22 sites Currently 32 sites Redirection network touches six clouds (DE, FR, IT, RU, UK, US) plus CERN Redirectors ready for ES and Asia regions At start of the FDR 22 sites Currently 32 sites Redirection network touches six clouds (DE, FR, IT, RU, UK, US) plus CERN Redirectors ready for ES and Asia regions

efi.uchicago.edu ci.uchicago.edu 8 Basic redirection functionality Direct access from clients to sites Redirection to non-local data (“upstream”) Redirection from central redirectors to the site (“downstream”) Uses a host at CERN which runs set of probes against sites

efi.uchicago.edu ci.uchicago.edu 9 Redirectors - regional and global 9 Service monitor

efi.uchicago.edu ci.uchicago.edu 10 Connectivity matrix Survey revealed complex security dependencies on various voms and xrootd clients found at sites

efi.uchicago.edu ci.uchicago.edu 11 Cost matrix measurements Cost-of-access: (pairwise network links, storage load, etc.)

efi.uchicago.edu ci.uchicago.edu 12 Comparing local to wide area performance Ping time (ms) read time (s) local Each site can check its connectivity and IO performance for copy and direct read

efi.uchicago.edu ci.uchicago.edu 13 Programmatic Hammer Cloud tests Defined a set of Hammer Cloud tests that probe the infrastructure and which collect measures of various data access patterns Setup by Johannes and Federica using Higgs  WW, and a SUSY D3PD analysis – (Root 5.30) HWW analysis code which analyzes NTUP SMWZ – (Root 5.34) HWW analysis code which analyzes NTUP SMWZ – (Root 5.32) SUSY analysis code which analyzes NTUP SUSYSKIM (p1328, p1329)

efi.uchicago.edu ci.uchicago.edu 14 Hammer Cloud testing Pre-placed, site-unique SUSY and Higgs datasets at all sites Realistic, typical analysis templates for SUSY D3PD maker and Higgs analysis New pilot equipped for stage-in or direct access with XrootD Choose ANALY queue, and redirector Submission runs for (both modes): – Phase 1: Local performance – Phase 2: Nearby performance (e.g. within a cloud) – Phase 3: Far-away performance

efi.uchicago.edu ci.uchicago.edu 15 Test datasets SUSY data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 data12_8TeV physics_JetTauEtmiss.merge.NTUP_SUSYSKIM.r4065_p1278_p1328_p1329_tid _00 SMWZ data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 data12_8TeV physics_Muons.merge.NTUP_SMWZ.f479_m1228_p1067_p1141_tid _00 Each of these datasets gets copied to a version with site-specific names in order to so as to automatically test redirection access and to provide a benchmark comparison

efi.uchicago.edu ci.uchicago.edu 16 Test dataset distribution Both sets of test datasets distributed to most sites with small amounts of cleanup left. These datasets will be used to gather reference benchmarks for the various access configuration

efi.uchicago.edu ci.uchicago.edu 17 Queue configurations This turns out to be the hardest part Providing federated XRootD access exposes the full extent of heterogeneity of sites, in terms of schedconfig queue parameters Each site’s “copysetup” parameters seems to differ, and specific parameter settings need to be tried in the Hammer Cloud job submission scripts using –overwriteQueuedata Amazingly, in spite of this there are a good fraction of FAX- functional sites

efi.uchicago.edu ci.uchicago.edu 18 First phase of HC tests: local access HC run – – HWW code with regular SMWZ input, FAX directIO, production version pilots – This is for access to local data, but via direct access xrootd Results: – 26 sites in the test – 16 sites with job successes – 3 sites where no job started/finished during test – (CERN, ROMA1, OU_OCHEP_SWT2) – 1 site does not have input data (GLASGOW) – 1 site blacklisted (FZU) – 1 site used xrdcp instead of directIO (BNL) – 4 sites with 100% failures (EDCF, IHEP, JINR, LANCS) – 4 sites with job successes and failures – (FRASCATI, NAPOLI, LRZ, RAL) – LRZ experienced again xrootd crashes – SLAC jobs finally succeed Johannes, 3 weeks ago

efi.uchicago.edu ci.uchicago.edu 19 HC efficiencies for selected sites

efi.uchicago.edu ci.uchicago.edu 20 First phase of HC tests: local access HC run – – HWW code with regular SMWZ input, FAX directIO, production version pilots – This is for access to local data, but xrdcp to scratch Results: – 28 sites in the test – 17 sites with job successes – 12 sites with actual xrdcp job successes – 7 sites used directIO AGLT2, LRZ, MPPMU, MWT2, SLAC, SWT2_CPB, WUPPERTAL – 3 sites with all job failures IHEP, JINR, SWT2_CPB – 3 sites with no jobs started during test ECDF, CAM, CERN – 1 site with black-listed ANALY queue OU_OCHEP_SWT2 – 2 sites with no input data LANCS, GRID-LAL Johannes, 2 weeks ago

efi.uchicago.edu ci.uchicago.edu 21 Systematic FDR load tests in progress Choose analysis queue & FAX server sites, #jobs, #files Choose access type: copy files or direct ROOT access (10% events, 30 MB client cache) Record timings in CERN Choose analysis queue & FAX server sites, #jobs, #files Choose access type: copy files or direct ROOT access (10% events, 30 MB client cache) Record timings in CERN Adapted WAN framework for specific FDR load tests

efi.uchicago.edu ci.uchicago.edu 22 Systematic FDR load tests in progress Individual job lists + links back to Panda logs Individual job lists + links back to Panda logs Drill down

efi.uchicago.edu ci.uchicago.edu 23 Systematic FDR load tests in progress US cloud results. 10 jobs * 10 SMWZ files ~ 50GB CPU limited Factors affecting spreads: pair-wise network latency, throughput, storage “business”

efi.uchicago.edu ci.uchicago.edu 24 Systematic FDR load tests in progress US cloud results

efi.uchicago.edu ci.uchicago.edu 25 Systematic FDR load tests in progress EU cloud results

efi.uchicago.edu ci.uchicago.edu 26 Systematic FDR load tests in progress EU cloud results destination events/sBNL-ATLASCERN-PRODECDFROMA1QMUL source BNL-ATLAS CERN-PROD ECDF ROMA QMUL MB/sBNL-ATLASCERN-PRODECDFROMA1QMUL source BNL-ATLAS CERN-PROD ECDF ROMA QMUL

efi.uchicago.edu ci.uchicago.edu 27 Controlled site “load” testing Two sites being in IT cloud read by jobs running at CERN

efi.uchicago.edu ci.uchicago.edu 28 Federated traffic seen in the WLCG dashboard

efi.uchicago.edu ci.uchicago.edu 29 Federation traffic Modest levels now will grow when in production Oxford and ECDF switched to xrootd for local traffic Prague users reading from EOS Co-located Tier 3 client  Tier 2 server

efi.uchicago.edu ci.uchicago.edu 30 Studies from Shuwei Ye at BNL Comparing wall and CPU times for access from Tier3 to datasets at BNL, NET2 and RAL (only BNL results shown) Concludes nearby redirector reduces time to process (validates ATLAS redirection model) Usual performance hit for “long reach” datasets over slow networks (to RAL) More systematic studies to come.

efi.uchicago.edu ci.uchicago.edu 31 ATLAS throughputs (from US) FAX traffic a tiny fraction of the total ATLAS throughput (for now)

efi.uchicago.edu ci.uchicago.edu 32 By destination (FTS + FAX)

efi.uchicago.edu ci.uchicago.edu 33 FAX by source cloud

efi.uchicago.edu ci.uchicago.edu 34 FAX by destination cloud

efi.uchicago.edu ci.uchicago.edu 35 Daily FAX transfer UDP collector down

efi.uchicago.edu ci.uchicago.edu 36 Conclusions The FDR has been a good exercise in exposing a number of site & system integration issues – Site specific client differences  limited proxy check not always working – Non-uniform copysetup parameters in schedconfig for sites – Lack of fault checking in the rungen script for read failures – Tweaks necessary to brokering to allow sending jobs to sites missing datasets In spite of this, much progress: – New functionality in the pilot to handle global paths without using dq2-client & forcing python 2.6 compatibility at all sites – First phase of programmatic HC stress testing nearing completion (local site access) – Some FAX accesses from Tier 3s – Test datasets in place Next steps – Programmatic HC stress tests for regional data access (Phase 2) – Address remaining integration issues above & continue to validate sites – Recruit, acquire feedback from early-adopting users – Outsource monitoring services where possible to WLCG, including central UDP collectors, availability probes, etc. – Global and Rucio namespace mapping, dev. of new N2N module – Set a timeframe for an ATLAS requirement of federating xrootd services at sites

efi.uchicago.edu ci.uchicago.edu 37 Thanks A hearty thanks goes out to all the members of the atlas-adc- federated-xrootd group, especially site admins and providers of redirection & monitoring infrastructure Special thanks to Johannes and Federica for preparing HC FAX analysis stress test templates and detailed reporting on test results Simone & Hiro for test dataset distribution & Simone for getting involved in HC testing Paul, John, Jose for pilot and wrapper changes Rob for testing and pushing us all Wei for doggedly tracking down xrootd security issues & other site problems & Andy for getting ATLAS’ required features into xrootd releases

efi.uchicago.edu ci.uchicago.edu 38 EXTRA SLIDES

efi.uchicago.edu ci.uchicago.edu 39 Data federated (1) Top 100 sites used by ATLAS (bold=FAX accessible) * Includes tape, which we do not federate * *

efi.uchicago.edu ci.uchicago.edu 40 Data federated (2) Top 100 sites used by ATLAS (bold=FAX accessible) GRIF-LAL IN2P3-LAPP

efi.uchicago.edu ci.uchicago.edu 41 Data federated (3) Top 100 sites used by ATLAS (bold=FAX accessible)

efi.uchicago.edu ci.uchicago.edu 42 Full SMWZ DATA+MC coverage (>96% of total 694 datasets) Average number of replicas ~2.5

efi.uchicago.edu ci.uchicago.edu 43 SkimSlimService FAX killer app. Free physicists from dealing with big data Free IT professionals from dealing with physicists, let them deal with what they do the best - big data. Efficiently use available resources (over the pledge, OSG, ANALY queues, EC2)

efi.uchicago.edu ci.uchicago.edu How it works? Use FAX to access all the data without overhead of staging. Use optimally situated replicas. (possible optimization - production D3PDs preplaced at just several sites, maybe even just one) Physicists request skim/slim through a web service. Could add a few variables in flight. Produced datasets registered in the name of requester. Delivered to a site requested. As all of the data is available in FAX, one can do skims of not only production D3PDs but of any flat ntuple, or multi-pass SkimSlims.

efi.uchicago.edu ci.uchicago.edu SSS - QOS Timely result is a paramount! Several levels of service depending on size of input and output data and importance: Example: 1.<1TB (input+output) - 2 hours service – this one is essential, as only in this case people will skim/slim to only variables they need without thinking of – “what if I forget something I’ll need” TB – 6 hours TB – 24 hours 4.Extra fast delivery: at EC2 but comes with a sticker tag

efi.uchicago.edu ci.uchicago.edu SkimSlimService 1 We have no dedicated resources for this I used UC3 but any queue that has cvmfs will suffice. 2 Modified version of filter-and-merge.py used. 3 Currently under my name as I don’t have production role. Web site at CERN gets requests, shows their status Web site at CERN gets requests, shows their status Handmade server 1 receives web queries, collects info on datasets, files, trees, branches Handmade server 1 receives web queries, collects info on datasets, files, trees, branches Executor at UC3 1 gets tasks from the DB, creates, submits condor SkimSlim jobs 2 makes and registers resulting DS 3 Executor at UC3 1 gets tasks from the DB, creates, submits condor SkimSlim jobs 2 makes and registers resulting DS 3 OracleDB at CERN Stores requests, splits them in tasks, serves as a backend for the web site OracleDB at CERN Stores requests, splits them in tasks, serves as a backend for the web site

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