CVMFS

CVMFS (the CernVM File System) is a network file system, originally developed as part of the CernVM project as a way to deliver software in a fast, scalable and reliable manner. It has been designed with the following features:

• Built from common, widely-supported technologies.
• Uses local caches for simple scaling.
• Performance is close to that of locally-installed software, often exceeding that of NFS or AFS.

Providing software via CVMFS removes the need to install applications locally at every site, greatly simplifying the deployment process. Software updates need to be applied once to the application instance in CVMFS, rather than being pushed out to multiple sites.

If you need to use software provided by experiments at CERN or elsewhere, or require access to standard libraries or dependencies, you are strongly recommended to check whether these exist in CVMFS; if they are, then using the CVMFS copy will likely be significantly easier than trying replicate the environment and build the software locally.

Further information about using CVMFS can be found here:

• https://twiki.atlas-canada.ca/bin/view/AtlasCanada/ATLASLocalRootBase
• https://www.gridpp.ac.uk/wiki/A_quick_guide_to_CVMFS

CVMFS at Glasgow

On PPE Linux machines, the CVMFS repositories can often be found mounted under /cvmfs. These repositories are read-only, but can otherwise be accessed like any other local directory:

$ ll /cvmfs
total 0
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 ams.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 atlas.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 atlas-condb.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 atlas-nightlies.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 cms.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 geant4.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 grid.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 ilc.desy.de
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 lhcb.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 na61.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 na62.cern.ch
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 na62.egi.eu
dr-xr-xr-x. 2 root root 0 Apr 11 09:05 sft.cern.ch