CVMFS

CVMFS is a network file system based on HTTP and optimized to deliver experiment software in a fast, scalable, and reliable way. It was originally developed as part of the CernVM project and has the following features:

• Caching, Read-only
• Based on very standard technologies - outgoing http, fuse...
• Scales very easily with additional squid caches
• File checksums (currently SHA1) are verified against a trusted catalog obtained over HTTPS
• File based deduplication as a handy side effect of the signed file catalog
• Uses fuse to mount a virtual filesystem (based on a signed-catalog downloaded form the server)
• Performance is close to a locally installed sofwtare after initial cache population
• Jobs run faster than with either NFS or AFS
• Removes the need for local software install jobs at every site

(borrowed from the gridpp CVMFS page https://www.gridpp.ac.uk/wiki/RAL_Tier1_CVMFS, some instructions are on the page https://twiki.atlas-canada.ca/bin/view/AtlasCanada/ATLASLocalRootBase)

CVMFS at Glasgow

On the local batch and desktops the CVMFS repositories are mounted under the /cvmfs directory. Currently the ams.cern.ch, atlas.cern.ch, atlas-condb.cern.ch, atlas-nightlies.cern.ch, cms.cern.ch, geant4.cern.ch, lhcb.cern.ch, na61.cern.ch and sft.cern.ch are repositories are available.

[~]$ ll /cvmfs
total 5
dr-xr-xr-x 2 root  root     0 Nov  8 13:28 ams.cern.ch
drwxrwxr-x 1 cvmfs cvmfs    0 Mar  5  2012 atlas.cern.ch
drwxr-xr-x 2 cvmfs cvmfs    0 Nov  8 13:28 atlas-condb.cern.ch
drwxr-xr-x 2 cvmfs cvmfs    0 Nov  8 13:28 atlas-nightlies.cern.ch
dr-xr-xr-x 2 root  root     0 Nov  8 13:28 cms.cern.ch
drwxr-xr-x 2 cvmfs cvmfs    0 Nov  8 13:28 geant4.cern.ch
dr-xr-xr-x 2 root  root     0 Nov  8 13:28 lhcb.cern.ch
dr-xr-xr-x 2 root  root     0 Nov  8 13:28 na61.cern.ch
dr-xr-xr-x 2 root  root     0 Nov  8 13:28 sft.cern.ch

-- AndrewPickford - 2013-11-11