Fabric

Each of the centres participating in the WLCG project must manage a large collection of computers and storage systems, referred to as the fabric. Installing and regularly upgrading the necessary software manually is labour intensive. In addition, each of the Tier-1 centres must maintain large disk and tape servers which need to be upgraded regularly.

Management

Fabric management systems, such as the Quattor system developed at CERN, automate the running of a service based on large numbers of commodity components – always ensuring that the correct software is installed, from the operating system all the way to the experiment-specific physics libraries.

The fabric management software also publishes this information so that it is available to the overall Grid scheduling system, which decides which centres are able and available to run a particular job.

Disk & Tape

WLCG centres use specialised tools to manage the massive disk and magnetic tape storage systems needed for LHC, and allow applications to access the data for simulation and analysis, independent of the storage medium (tape or disk) that the data resides on.

These tools include the dCache system developed at the DESY laboratory in Germany, the ENSTORE system at the Fermi National Accelerator Laboratory and the CASTOR system developed at CERN.