Tier-2  Data Analysis  MC simulation  Import data from Tier-1 and export MC data CMS GRID COMPUTING AT THE SPANISH TIER-1 AND TIER-2 SITES P. Garcia-Abia a, J.M. Hernández a, F. Martínez b, G. Merino b, M. Rodríguez b, F.J. Rodríguez-Calonge a a CIEMAT, Madrid, Spain b PIC, Barcelona, Spain Abstract CMS has chosen to adopt a distributed model for all computing in order to cope with the requirements on computing and storage resources needed for the processing and analysis of the huge amount of data the experiment will be providing from LHC startup. The architecture is based on a tier-organized structure of computing resources, based on a Tier-0 center at CERN, a small number of Tier-1centers for mass data processing, and a relatively large number of Tier-2 centers where physics analysis will be performed. The distributed resources are inter-connected using high-speed networks and are operated by means of Grid toolkits and services. We present in this poster, using the Spanish Tier-1 (PIC) and Tier-2 (federated CIEMAT-IFCA) centers as examples, the organization of the computing resource in CMS together with the CMS Grid Services, built on top of generic Grid Services, required to operate the resources and carry out the CMS workflows. The Spanish sites contribute with 5% of the CMS computing resources. We also present the current Grid-related computing activities performed at the CMS computing sites, like high-throughput and reliable data distribution, distributed Monte Carlo production and distributed data analysis, where the Spanish sites have traditionally played a leading role in development, integration and operation. CMS Computing Model Tier-0  Accepts data from DAQ  Prompt reconstruction  Archives and distributes data to Tier-1’s Tier-1  Real data archiving  Re-processing  Calibration  Skimming and other data- intensive analysis tasks  MC data archiving Data Transfer DB TMDB Data Book- keeping DB RefDB LCG replica catalogue User Interface MC Production McRunjob Analysis Tool CRAB Job Monitoring & Bookkeeping BOSS Data Location DB PubDB Resource Broker Grid Information System Computing Element Worker Node Storage Element Data Transfer PhEDEx Site Local Catalogue Application Database LocalGlobalLocal or remote Computing resource Interaction Job flow Data flow Workload Management System Data Management System CMS Computing Services/Workflows End 2005End 2006End 2007 CPU (kSI2k) Disk (TB) Tape (TB) WAN (Gbps)110 End 2005End 2006End 2007 CPU (kSI2k) Disk (TB) Tape (TB)--- WAN (Gbps)1110 Hardware Resources PIC Tier-1 Tier-2 Spain CIEMAT-IFCA  Data Distribution Computing Grid Activities Done with PhEDEx, the CMS large scale dataset replica management system. Managed, reliable, routed multi-hop transfers. Includes pre-staging data from tape Demonstrated sustained transfer rates of ~3TB/day to the Spanish sites.  Distributed Data Analysis Spanish sites host ~15% of CMS data (~15 Mio. events, ~15 TB) ~10K analysis jobs ran at the Spanish sites so far  Distributed Monte Carlo Production Leading role of the Spanish sites in MC production in LCG Grid in the areas of development, integration and operation ~ 15 Mio. MC events produced in LCG Production activities  LCG Service Challenge 3  CMS goal: exercise under realistic conditions bulk data transfer and data serving infrastructure SC3 Throughput phase (July 2005)  Goal: high throughput transfer + storage system test  Sustained rate disk-to disk of ~4TB/day (50 MB/s avg) for 2 weeks to PIC Tier-1 SC3 Service phase (September-November 2005)  Goal: concurrent data transfer and data access from storage  Test Data Management components (data transfer system, data publication, data catalogues, storage systems) as well as Workload Management components (job submission, monitoring, etc) in a large-scale real use.  Automatic data publication for analysis as data get transferred  Automatic analysis job submission as data get published  15 TB of data transferred to the Spanish sites  10K jobs run at the Spanish sites (~20% of the CMS SC3 jobs run in LCG)  175 MB/s aggregate analysis job read throughput at PIC Tier-1 and 75 MB/s at Spain Tier-2 Integration/test activities For more information, contact: José M. Hernández, CIEMAT, Particle Physics Division E-28040, Madrid, Spain