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CMS at CNAF Tier-1: Pre-Challenge Production and Data Challenge 04

CMS at CNAF Tier-1: Pre-Challenge Production and Data Challenge 04. D.Bonacorsi (CNAF/INFN e CMS Bologna). Outline. Introductory overview : CMS Pre-Challenge Production (PCP) Data Challenge (DC04)  ideas, set-up, results: main focus on INFN contribution DC04: the lessons learned

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CMS at CNAF Tier-1: Pre-Challenge Production and Data Challenge 04

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  1. CMS at CNAF Tier-1: Pre-Challenge Production and Data Challenge 04 D.Bonacorsi (CNAF/INFN e CMS Bologna)

  2. Outline • Introductory overview: • CMS Pre-Challenge Production (PCP) • Data Challenge (DC04)  ideas, set-up, results: main focus on INFN contribution • DC04: the lessons learned •  post-mortem analysis in progress: preliminary results • the CNAF Tier-1 role and experience in PCP-DC04 • on the above items, discussion on successes/failures, problems/solutions/workarounds, still open issues… III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  3. Pre-Challenge Production: PCP (Jul. 03 - Feb. 04) Simulation and digitization of data samples needed as input for DC Transfer to CERN: ~1TB/day for several months PCP Strategy: “it could not fail”, so mainly non-grid production… …but use grid prototypes (CMS/LCG-0, LCG-1, Grid3)  ~70M Monte Carlo events (20M with Geant-4) produced, 750K jobs, 3500 KSI2000 months, 80 TB of data  Digitization still going-on “in background” CMS PCP-DC04 overview Validation of CMS computing model  large scale test of the computing/analysis models on a sufficient number of T0, T1, T2 sites Generation Simulation PCP Digitization • Data Challenge: DC04 (Mar. - Apr. 04) • Reconstruction and analysis on CMS data sustained over 2 months at the 5% of the LHC rate at full luminosity  25% of start-up lumi • Data distribution to Tier-1,Tier-2 sites • DC Strategy: • Sustain a 25Hz reconstruction rate in the Tier-0 farm • register data and metadata to a world-readable catalogue • transfer reconstructed data from Tier-0 to Tier-1 centers • analyze reconstructed data at the Tier-1’s as they arrive • publicize to the community the data produced at Tier-1’s • monitor and archive resources and process info Not a CPU challenge, but aimed to the demostration of feasibility of the full chain Reconstruction DC04 Analysis III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  4. CMS ‘permanent’ production DC04 start PCP start • since 03, higher scale w.r.t the past • ~10 months of continuous running • no more time for significant develop. • processes between production cycles • fixing an always-running engine.. … ‘Spring02 prod’ ‘Summer02 prod’ CMKIN CMSIM + OSCAR Digitisation The system is evolving into a permanent production effort… Strong contribution of INFN and CNAF Tier-1 to CMS past&future productions: 252 assid’s in PCP-DC04, for all production step, both local and (when possible) Grid III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  5. Dataset metadata RLS Computer farm JDL Grid (LCG) Scheduler LCG-0/1 DAG Grid3 DAGMan (MOP) Job metadata job Push data or info Chimera VDL Virtual Data Catalogue job job Planner Pull info job PCP set-up: a hybrid model by C.Grandi Phys.Group asks for a new dataset Production Manager defines assignments RefDB shell scripts Data-level query Local Batch Manager BOSS DB Job level query McRunjob + plug-in CMSProd Site Manager starts an assignment III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  6. PCP @ INFN statistics (1/4) CMS production steps: Generation Simulation ooHitformatting Digitisation Generation step (all CMS) Generation step (INFN only) contribute to this slope Jun – mid-Aug 03 ~79 Mevts in CMS ~9.9 Mevts (~13%) done by INFN (strong contribution by LNL) III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  7. PCP @ INFN statistics (2/4) CMS production steps: Generation Simulation ooHitformatting Digitisation Simulation step [CMSIM+OSCAR] (all CMS) Simulation step [CMSIM+OSCAR] (INFN only) Jul – Sep 03 ~75 Mevts in CMS ~10.4 Mevts (~14%) done by INFN (strong contribution by CNAF T1+LNL) III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  8. PCP @ INFN statistics (3/4) CMS production steps: Generation Simulation ooHitformatting Digitisation ooHitformatting step (all CMS) ooHitformatting step (INFN only) Dec 03 end-Feb 04 ~37 Mevts in CMS ~7.8 Mevts (~21%) done by INFN III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  9. PCP @ INFN statistics (4/4) CMS production steps: Generation Simulation ooHitformatting Digitisationcontinued through DC! 2x1033 digitisation step (all CMS) DC04 Note: strong contribution to all steps by CNAF T1 but only outside DC04 (on DC too hard for CNAF T1 to be a RC also!!) 24 Mevents, 6 weeks Feb 04 May 04 2x1033 digitisation step (INFN only) ~ 43 Mevts in CMS ~ 7.8 Mevts (~ 18%) done by INFN III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  10. PCP grid-based prototypes Constant work of integration in CMS between: CMS softwareand production tools  evolving EDG-XLCG-Y middleware in several phases:  CMS “Stress Test” stressing EDG<1.4, then: PCP on the CMS/LCG-0 testbed PCP on LCG-1 … towards DC04 with LCG-2 EU-CMS: submit to LCG scheduler  CMS-LCG “virtual” Regional Center 0.5 MevtsGeneration [“heavy” pythia] (~2000 jobs ~8 hours* each, ~10 KSI2000 months) ~ 2.1 MevtsSimulation [CMSIM+OSCAR] (~8500 jobs ~10hours* each, ~130 KSI2000 months) ~2 TB data OSCAR: ~0.6 Mevts on LCG-1 * PIII 1GHz CMSIM: ~1.5 Mevts on CMS/LCG-0 III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  11. Tier-0 Tier-0 data distribution agents EB GDB Tier-2 Tier-2 Tier-2 Physicist Physicist Physicist ORCA RECO Job T2 storage T2 storage T2 storage Tier-1 Tier-1 Tier-1 Tier-1 agent Tier-1 agent Tier-1 agent ORCA Local Job ORCA Local Job ORCA Local Job RefDB IB TMDB MSS MSS MSS T1 storage T1 storage T1 storage fake on-line process ORCA Analysis Job ORCA Analysis Job ORCA Analysis Job ORCA Grid Job ORCA Grid Job ORCA Grid Job POOL RLS catalogue Castor Global DC04 layout by C.Grandi LCG-2 Services III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  12. DC04 key points (1/2) Adapted from a talk by C.Grandi, EGEE Cork Conf, April 19th, 2004 • Maximize reconstruction efficiency • no interactions of Tier-0 jobs with outside components • Automatic registration and distribution of data • via a set of loosely coupled agents • Support a (reasonable) variety of different data transfer tools and set-up • SRB (RAL, GridKA, Lyon, with Castor, HPSS and Tivoli SE) • LCG-2 Replica Manager (CNAF, PIC, with Castor-SE) • SRM (FNAL, with dCache/Enstore) • and this reflects into 3 different Export Buffers at CERN (T0  T1’s) • Use a single global file catalogue (accessible from all T1’s) • RLS used for data and metadata (POOL) by all transfer tools • Key role of the Transfer Management DB (TMDB) • a context for agents inter-communication • Failover systems and automatic recovery see later III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  13. Redundant monitor/archive of info on resources and processes: MonaLisa used on almost all resources GridICE used on all LCG resources LEMON on all IT resources Ad-hoc monitoring of TMDB information DC04 key points (2/2) • Strategy for job submission at RCs left to their choice • e.g. LCG-2 in Italy/Spain see later • Data availability for user analysis: work in progress… • grant data access to users • prototyping user analysis models on LCG… III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  14. LCG-2 components in DC Used at CNAF/PIC T1s for the full DC04 chain (but the T0 reco) (see ‘DC strategy’ on slide 3) • register all data and metadata to a world-readable catalogue • official RLS service provided by CERN/IT with Oracle backend • ~570k files registered (each with 5-10 PFN’s and 9 metadata attributes) • Good performance as a global file catalogue: • Registration of files by both production and all transfer tools • Fast enough if using the appropriate tools (e.g. LRC C++ API) • Bad performance as a global metadata catalogue (up to ~1 KB metadata per file) • RLS replica at CNAF (ORACLE multi-master mirroring): may be tested in the next future.. • transfer the reconstructed data from Tier-0 to Tier-1 centers • full data transfer chain implemented using LCG-2 Replica Manager between LCG-2 SEs • (Castor-SEs at CNAF/PIC, classic disk-SEs at CERN (Export Buffer), CNAF, LNL, PIC) • analyze the reconstructed data at the Tier-1’s as data arrive • dedicated bdII (EIS+LCG)  CMS may add resources and/or remove problematic sites • real-time analysis with dedicated RB (using above bdII) + standard RBs (CNAF,LNL,PIC) • 2 UIs at CNAF, UIs also at LNL,PIC • CE+WNs at CNAF, LNL, PIC+CIEMAT • publicize to the community the data produced at Tier-1’s • in progress but straightforward using the usual Replica Manager tools • end-user analysis at the Tier-2’s(not really a DC04 milestone) • first attempts succeeded, more in progress • monitor and archive resource and process information • dedicated GridICE server deployed at CNAF and monitoring all involved LCG-2 resources III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  15. Post-mortem analysis is in progress (see later for CNAF T1), nevertheless in general: the full chain is demonstrated but for limited amount of time reconstruction/data-transfer/analysis may run at 25 Hz at T0: 2200 running jobs/day (on ~500 CPU’s), 4 MB/s produced and distributed to each Tier-1, 0.4 files/s registered to RLS (with POOL metadata) different T1 performances, related to architectural choices on the EB Data transfer infrastructure (with LCG-2 system and use of classical SE-EB) used by CNAF and PIC showed very good performances main areas for future improvements have been identified Reduce number of files (i.e. increase <#events>/<#files>) more efficient use of bandwidth fixed time to “start-up” dominates command execution times (e.g. java in replicas..) address scalability of MSS systems Improve handling of file metadata in catalogues RLS too slow both inserting and extracting full file records introduce the concept of “file-set” to support bulk operations real-time analysis during DC04 was demonstrated to be possible! But: need a clean environment! ~ 15k jobs submitted via LCG-2 ran through the system problems e.g. filling the RB disk space having sandboxes of about 20 MB DC04: preliminary results III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  16. part 2: CNAF Tier-1 role in DC04 (and experience gained) III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  17. CMS resources at CNAF T1 in DC04 • CNAF Tier-1 is young, new resources in the brand new Tier-1 hall in Bologna •  set-up and tests during PCP digitization! •  CMS DC04 was an important Data Challenge experience at CNAF Tier-1 • Storage: a Castor SE (disk buffer: 4 TB) and a classical disk-only SE (4 TB) •  more could be made available, but there was no need • Network: CNAF interconnected to GARR-B backbone at 1 Gbps, e.g. from the Export Buffer to the T1 SEs (FE only for CE/WNs LAN) • CPUs: 43 boxes allocated to CMS + ~25 shared, SMicro motherboard, dual Xeon 2.4 GHz, hyper-thread on, IDE disks 2x60 GB, 2 GB RAM •  1. CPU power for PCP and real-time analysis in DC04 • 2. services needed for the DC • First experience with the new tape library STK L5500 with IBM LTO2 drives ( all what follows: adapted from 2 talks by D.Bonacorsi, CMS-CPT week, May 12nd, 2004: see references) III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  18. DC04 workflow for INFN Transfer Management DB disk-SE Export Buffer disk-SE Export Buffer disk-SE Export Buffer CNAF T1 data flow TRA-Agent query db local MySQL update db tape library T1 Castor SE Legnaro T2 SAFE-Agent REP-Agent T1 disk-SE T2 disk-SE TRA-Agent:T0 (SE-EB)T1(Castor) Transfer Agent REP-Agent: T1(Castor)T1(disk)/T2(disk) Replica Agent SAFE-Agent:migration-check procedure III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  19. CNAF T1 data transfer agents • use of LCG-2 Replica Manager for data transfer • modular infrastructure  versatile management of data flow (see ‘ ‘) • TRA-Agent:T0 (SE-EB)T1(Castor) Transfer Agent • task: T1 main data flow management from SE-EB, supposed to be up&running 24/7 • real-time reconfiguration of transfer parameters possible • implementation: C++, ran on LCG2 UI “shared” • REP-Agent: T1(Castor)T1(disk)/T2(disk) Replica Agent • task: replicate files to disk-SEs for fake analysis, target can be T1/T2/both • agent code able to: • guarantee authomatic file-organization at destination • advertising procedure to inform the “fake-analysis people” about new files • agent “cloned” to deal with Castor stager scalability problems • implementation: C++, ran on LCG2 UI “CMS-only” (the same used for analysis at CNAF) • SAFE-Agent:migration-check procedure • task: check if migration to tape occurred and label the files as SAFE on the TMDB • rfio/nsls commands less verbose in tapeserver logs w.r.t the edg-gridftp-X family, • so procedure completely re-engineered in the middle of DC04 (separate agent) • implementation: Perl cron job on LCG2 UI “shared” III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  20. DC data transfer to CNAF T1 • first Validation Data arrived at CNAF Tier-1 on Saturday, March 6th, 17:23 CERN time • last files arrived at CNAF Tier-1 on Sunday, May 2th, 06:43 CERN time DC04 data time window: 51 (+3) days March 11th – May 3rd exercise with ‘big’ files (see later for details) • A total of >500k files and ~6 TB of data transferred T0  CNAF T1 • max nb.files per day is ~45000 on March 31st , • max size per day is ~400 GB on March 13th (>700 GB considering the “Zips”) III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  21. An example: T0 ramp-up to 200 jobs SE-EB The story: T0 ramped up production, increasing rate predicted to be showing up in the EBs at late night Here you see it for both SE-EB and e.g. CNAF Castor SE Castor SE at CNAF T1 eth I/O CPU load III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  22. An example: increasing the T0 rate Just an example of how the data transfer system kept the pace  analysis of the chain SE-EB  CNAF Castor SE during last week of DC04 SE-EB CNAF Apr 25 Apr 30 May 2 III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  23. An example: Replicas to disk-SEs CNAF T1 Castor SE eth I/O input from SE-EB CNAF T1 Castor SE TCP connections Just one day: Apr, 19th RAM memory CNAF T1 disk-SE eth I/O input from Castor SE green Legnaro T2 disk-SE eth I/O input from Castor SE III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  24. Data management in the chain disk-SE EB  CNAF/PIC T1’s Data transfer between LCG-2 SEs Set-up: Export Buffer at Tier-0 with classical disk-based SE  3 SE machines with 1 TB each a Castor-SE at CNAF T1 and at PIC T1  but different underlying MSS solution Data transfer tool: • CNAF: Replica Manager CLI (+ LRC C++ API for listReplicas only) • copy a file and inherently register it to the RLS, with file-size info stored in the PFN ‘size’ attribute (i.e. in the LRC): used to check success of replica • over-head introduced by CLI java processes • repetition of failed replicas is needed  effect on transfer efficiency • PIC: globus-url-copy + LRC C++ API • copy a file then register to the RLS (‘add PFN’), no file-size check • faster • less safe regarding the quality-check of replica operations?  RM looked “safer-but-slower” i.e. offers more warranty against failed replicas, but this has a price.. • Anyway, both CNAF/PIC strategies offered good performances •  throughput mainly limited by sizes of files not by transfer tools III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  25. CNAF “autopsy” of DC04 1. Lethal injuries • Agents drain data from SE-EB down to CNAF T1 and • they ‘land’ directly on a Castor SE buffer •  it occurred that in DC04 these files were many and small • So: for any file on the Castor SE fs, a tape migration is • foreseen with a given policy, regardless of their size/nb..  this strongly affected data transfer at CNAF T1 (MSS below is tape lib STK L5500 with IBM LTO-2 tapes) • Castor stager scalability issues(more info: Castor ticket CT204339) many small files (mostly 500B-50kB)  bad performances of stager db for >300-400k entries (may need more RAM?) • CNAF fast set-up of an additional stager in DC04: basically worked • REP-Agent cloned to transparently continue replication to disk-SEs • tape library LTO-2 issues(more info: Castor ticket CT206668) high nb. segments on tape  bad tape read/write performances, LTO-2 SCSI errors, repositioning failures, slow migration to tape and delays in the TMDB “SAFE”-labelling, tape often labelled READONLY  inefficient tape space usage • A–posteriori question:maybe a disk-based Import Buffer in front of MSS? DC04 III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  26. CNAF “autopsy” of DC04 2. Non-lethal injuries • minor (?) Castor/tape-library issues • Castor filename length (more info: Castor ticket CT196717) • ext3 file-system corruption on a partition of the old stager • tapes blocked in the library • several crashes/hanging of the TRA-Agent (rate: ~ 3 times per week)  created from time to time some backlogs, nevertheless fast to be recovered •  post-mortem analysis in progress • experience with the Replica Manager interface e.g. files of size 0 created at destination when trying to replicate from Castor SE some data which are temporarily not accessible for stager (or other) problems on the Castor side •  needs further tests to achieve reproducibility and then Savannah reports • Globus-MDS Information System instabilities (rate: ~ once per week)  some temporary stop of data transfer (i.e. ‘no SE found’ means ‘no replicas’) • RLS instabilities (rate: ~ once per week)  some temporary stop of data transfer (cannot both list replicas and (de)register files) At this scale the debug is forced to adopt a statistical approach.. III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  27. Network: transferring ‘big’ files >3k files for >750 GB just at the end of DC04 CNAF T1 SE eth I/0 link utilization above 80% during all the last DC04 data transfer exercise. Global CNAF network activity monitored by NOC-GARR May 1st May 2nd ~340 Mbps (>42 MB/s) sustained for ~5 hours (max was 383.8 Mbps) • the network is not a problem: the throughput was limited by the small size of files III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  28. Summary on CNAF T1 role in CMS DC04 • CNAF-INFN is a very young T1, nevertheless worked basically fine and enjoyed the race all through DC04, from the first Validation Data file received on Saturday, March 6th, 17:23 CERN time, until the successful end of the “big” files exercise on 1st-3rd May. •  much effort and much learning, many key items raised for the future • Positive know-how gained in agent coding, configuration and optimization, • and in the overall data transfer infrastructure set-up and management • Useful experience about CMS interfacing to Tier-1 structure at CNAF • Good results in the LCG2-based data transfer, in the real-time analysis effort • and in the network tests with big files in the final rush • Typically, problems were of two types: • things one may expect in a DC (stretch a system, something breaks) • Castor SEs operational at CNAF, but data transfer affected by Castor issues related to the underlying MSS  what in front of MSS in the future? • Towards user analysis!Data access and end-user analysis hot topics now.. AL RCs involved! III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  29. General conclusions • CMS production world-wide evolving into a ‘permanent’ trend • Lessons from DC04 (so far): • full chain demonstrated for limited amount of time • several exercises successful and gave important feedback • know-how raised and areas for future improvements identified DC04 post-mortem goes on… • “is what we think happened really what happened?” • collate and correlate information from logs • generate statistical models of components • very high level of ‘baby-sitting’ of activity..  thanks to CNAF T1 personnel, LCG, EIS, IT DB @ Cern ! Thanks for “stoled-and-revised” slides to: P.Capiluppi, C.Grandi, A.Fanfani, T.Wildish, D.Stickland References: Agenda + slides from CMS CPT Week (“DC04-review day”): http://agenda.cern.ch/fullAgenda.php?ida=a041651 III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  30. Back-up slides III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  31. CMS production tools (OCTOPUS) RefDB Contains production requests with all needed parameters to produce the dataset and the details about the production process MCRunJob Tool/framework for job preparation and job submission Evolution of IMPALA: more modular (plug-in approach) BOSS Real-time job-dependent parameter tracking. The running job standard output/error are intercepted and filtered information are stored in BOSS database. The remote updator is based on MySQL. CMS production tools III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  32. Only CMSIM INFN Only OSCAR INFN III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  33. Only CMSIM CMS-LCG Only OSCAR CMS-LCG III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  34. CMS/LCG-0 testbed Joint project CMS-LCG-EDT a CMS-wide testbed based on the LCG pilot distribution, owned by CMS, with additional component installed with the help of LCG EIS Based on LCG pilot distribution (using GLUE, VOMS, GridICE, RLS) About 170 CPU’s and 4 TB disk Sites: Bari Bologna Bristol CERN CNAF Ecole Polytechnique Legnaro NCU-Taiwan Padova MIlano, U.Iowa, ISLAMABAD-NCP, IC, Brunel only in the deployment phase III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  35. POOL RLS catalogue Description of RLS usage Local POOL catalogue TMDB Tier-1 Transfer agent SRB GMCAT Replica Manager RM/SRM/SRB EB agents 4. Copy files to Tier-1’s Resource Broker 3. Copy/delete files to/from export buffers 5. Submit analysis job LCG ORCA Analysis Job Configuration agent 2. Find Tier-1 Location (based on metadata) 6. Process DST and register private data CNAF RLS replica 1. Register Files XML Publication Agent ORACLE mirroring Specific client tools: POOL CLI, Replica Manager CLI, C++ LRC API based programs, LRC java API tools (SRB/GMCAT), Resource Broker III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  36. RLS used as a POOL catalogue Register files produced at Tier-0 with their POOL metadata (converting POOL XML catalogue into the RLS) Query metadata to determine which Tier-1 to send files to Register/delete physical location of files on Tier-0 Export Buffers Transfer tools use catalogue to replicate files to Tier-1’s Local POOL catalogues at Tier-1’s are optionally populated Analysis jobs on LCG use the RLS through the Resource Broker to submit jobs close to the data Analysis jobs on LCG register their private data III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  37. A disk Import Buffer in front of a MSS in the future? SE-EB TMDB T1 TRA-Agent T1 SE-IB (Import Buffer) disk-SEs REP-Agent data flow File manipulation, grouping, … query db LTO-2 tape library update db T1 Castor buffer SAFE-Agent III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  38. CNAF filename length problem • Castor filename length (actually Castor-Murphy’s law…)  old issue… CNAF had replies to CT196717, Mar 11th • CNAF Castor installation is standard, but the staging- area configuration resulted in a Castor • filenames max lenght < length EVD* DC04 files  install later a special patched ‘longname’ version of the stager code for the new stager But DC04-show must go on!  my workaround: store files on Castor SE with GUID’s as filenames then restore original filenames when replicating data to disk-SEs for fake-analysis  worked (lot of work on agents logic..), did not affect data transfer performances  III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  39. PIC CNAF CLEANED AT_T1 NEW IN_BUFFER SAFE III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

  40. Different EB scenarios in DC04 Classic disk-based SE-EB and LCG-2 Replica Manager Basically working. See main talk for details • SRM+dCache EB at Cern and SRM+dCache interface to FNAL Enstore MSS • quite a few sw/hw component failures during DC04: • problems at DC start with system failures • MSS needed optimization to handle challenge load • needed to increase nb tape drives to handle nb files • needed to replace name space server to handle nb files • srmcp client hung for unknown reasons • cannot handle bad-files situations at both source and destination SRM • file does not exist..? file with different sizes..? • much non-authomatic interventions • SRB+MCat interface with different underlying MSS • Severe failures most of the DC time.. Mainly related to MCat unreliability • need much investigation and subsequent work.. III Workshop Calcolo-Reti INFN, Castiadas (CA) - May 24-28, 2004D.Bonacorsi

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