Tier-1

NDGF operates the Nordic WLCG Tier-1 center. A Tier-1 center provide computing and data storage services for several CERN experiments: ATLAS, ALICE and probably CMS in case of NDGF. The main services are:

1. Receive and store persistently its share of data from Tier-0 (at CERN). Types of data, volumes and periodicity of data transfers are defined by experiments
2. Provide computing power for data processing
3. Host experiment-specific databases and make them available for affiliated computing centers
4. Transfer data to and from other computing centers (Tier-1, Tier-2)
5. Host other experiment-specific services (VOBoxes and such)

Specifics of the Nordic Tier1 is that the facility is distributed across a very wide geographical area, in several nodes.

Tier-1 Facility

The Tier-1 nodes providing storage and computing services are located at 7-10 sites around the Nordic countries:

• CSC, The Finnish IT Center for Science, Espoo
• HPC2N, High Performance Computing Center North, Umeå
• NBI, The Niels Bohr Institute, Copenhagen
• NSC, National Supercomputer Center in Sweden, Linköping
• UiB, The University of Bergen, Bergen
• UiO, The University of Oslo, Oslo
• PDC, Center for Parallel Computers, Stockholm

The Nordic Tier-1 services

• Storage
  • The Storage of the Nordic Tier-1 is distributed over the 7 sites above. At one site a central database server is placed working as single point of entry for CERN
• Computing
  • The compute infrastructure is distributed all over the Nordic countries and is accessible aither through ARC or through gLite middleware.
• Services
  • The services running at the Nordic Tier-1.
• [Networking]
  • The network connectivity map
• Hardware Aquisition Status
  • The participating sites aquire hardware during the project

Tier-1 Operations

Meetings

Periodic Reports

Service Challenges

Service Challenges have been conducted by WLCG in order to test the inrastructure readiness.

• Service Challenge 3 (Summer 2005)
• Service Challenge 4 (Spring 2006)