Computing Infrastructure Status

LHCb Computing Status LHCb LHCC mini-review, February The LHCb Computing Model: a reminder m Simulation is using non-Tier1 CPU resources o MC data are stored at Tier0-1s, no permanent storage at these sites m Real data are processed at Tier0-1 (up to analysis)

LHCb Computing Status LHCb LHCC mini-review, February The life of a real LHCb event m Written out to a RAW file by the Online System o Files are 2 GBytes / 60,000 events / 30 seconds on average m RAW file is transferred to Tier0 (CERN-Castor) o Migrated to tape, checksum verified (can be deleted in Online) m RAW file is transferred to one of the Tier1s o Migrated to tape m RAW file is reconstructed at Tier0-1 o About 20 hours to create an rDST  rDST stored locally with migration to tape m When enough (4?) rDSTs are ready, they are stripped o at the local site o Data streams are created  possibly files are merged into 2 GB files o Merged streamed DSTs & ETCs created, stored locally and at CERN with tape migration  DST & ETC distributed to the 5 other Tier1s m Analysis takes place on these stripped DSTs at all Tier0-1

LHCb Computing Status LHCb LHCC mini-review, February A few numbers m RAW file - 2 GB, events, 30 s o 1500 files per day, 3 TBytes, 70 MB/s o 90 Mevts / day m Reconstruction: 20 h o 1500 CPUs permanently (200 to 300 per site) m rDST file - 2 GB, events m Stripped DSTs o In the computing TDR, very aggressive numbers for selection  Factor 10 overall reduction (after HLT) o Number of streams to be defined… Assume 20 balanced streams  One 2 GB DST, events originating from 4 RAW Mevts  Need to merge 16 DSTs (of 240 kevts each)  25 streamed DSTs per day and per stream (50 GB)  For 120 days of run, only 6 TB for each stream (3000 files)

LHCb Computing Status LHCb LHCC mini-review, February The LHCb Computing Grid (1) m Integrated system called DIRAC o DIRAC is a community (LHCb) Grid solution  based on Grid infrastructure services (storage and computing resources and services) o DIRAC provides a unified framework for all services and tools o DIRAC2 used since 2004 for production, 2006 for analysis o DIRAC3 being commissioned (full re-engineering) m DIRAC provides high level generic services o Data Management  Fully reliable file transfers  retries until successful  based on gLite FTS (File Transfer Service) using specific channels and network links (LHC Optical Private Network, OPN)  FTS used for all transfers but file upload from Worker Nodes  simple file upload commands  Implements failover and recovery mechanism for all operations  registers actions to be performed later (e.g. when site is available again)  Registration of all copies of files (called “replicas”)  For users, files only have a Logical File Name (LFN)

LHCb Computing Status LHCb LHCC mini-review, February The LHCb Computing Grid (2) o Workload Management  Prepares data (pre-stage) if not available online  Submits jobs to sites where data are available  using EGEE infrastructure (gLite WMS)  Monitors the progress of the job  Uploads output data and logfiles  Allows re-submission if job fails m DIRAC LHCb-specific services o Data Management  Registration of the provenance of files (Bookkeeping)  used for retrieving list of files according to user’s criteria  returns LFNs o Production tools  Definition of processing (complex) workflows  e.g. run 4 Gauss, 3 Boole and 1 Brunel “step”  Creation of jobs  manually (Production Manager)  automatically (using pre-defined criteria, e.g. when 4 rDSTs are ready, strip them using this workflow)

LHCb Computing Status LHCb LHCC mini-review, February DIRAC3 for first data taking m DIRAC3 being commissioned o Most components are ready, integrated and tested o Basic functionality (equivalent to DIRAC2) m This week: full rehearsal week o all developers are at CERN o Goal: follow progress of the challenge, fix problems ASAP m DIRAC3 planning (as of 15 Nov) o 30 Nov 2007: Basic functionality o 15 Dec 2007: Production Management, start tests o 15 Jan 2008: Full CCRC functionality, tests start o 5 Feb 2008: Start tests for CCRC phase 1 o 18 Feb 2008: Run CCRC o 31 Mar 2008: Full functionality, ready for CCRC phase 2 tests o Current status: on time with above schedule

LHCb Computing Status LHCb LHCC mini-review, February CCRC’08 for LHCb m Raw data upload: Online  Tier0 storage (CERN Castor) o Use DIRAC transfer framework  exercise two transfer tools (Castor rfcp, Grid FTP) m Raw data distribution to Tier1s o Reminder: CNAF, GridKa, IN2P3, NIKHEF, PIC, RAL o Use gLite File Transfer System (FTS)  based on the upcoming Storage Resource Manager (SRM) version 2.2 (just coming out) o Share according to resource pledges from sites m Data reconstruction at Tier0+1 o Production of RDST, stored locally o Data access using also SRM v2 (various storage back-ends: Castor and dCache) m For May: stripping of reconstructed data o Initially foreseen in Feb, but de-scoped o Distribution of streamed DSTs to Tier1s o If possible include file merging

LHCb Computing Status LHCb LHCC mini-review, February Tier1 resources for CCRC’08 m Data sharing according to Tier1 pledges o as of February 15 th (!!!) m LHCb SRM v2.2 space token descriptions are: o LHCb_RAW (T1D0) o LHCb_RDST (T1D0) o LHCb_M-DST (T1D1) o LHCb_DST (T0D1) o LHCb_FAILOVER (T0D1)  used for temporary upload in case of destination unavailability m All data can be scrapped after the challenge o Test SRM bulk removal m Based on 2 weeks run o 28,000 files (42 TB) m CCRC’08 in May o 4 weeks continuous running o Established services and procedures

LHCb Computing Status CCRC’08 first results m Tier0-Tier1 transfers o 5,000 files (7.5 TB) transferred to Tier1s using FTS + SRM v2  4 hours! o All Tier1’s RAW spaces work o Continuous transfer over WE m Plans o Adding automatic reconstruction now m Pit to Tier0 transfers o Sustained nominal rate for 6 days (60 MB/s)  Red line o 125 MB/s for one day o Tape migration followed  Green line  High peaks are Tier1 transfers m Plans o ½ rate today (50% duty cycle) o Nominal rate after (>10 days) LHCb LHCC mini-review, February

LHCb Computing Status m Questions? m More news tomorrow o LCG-LHCC meeting LHCb LHCC mini-review, February