The CernVM-File System (CernVM-FS) provides a scalable, reliable and low-
maintenance software distribution service. It was developed to assist High
Energy Physics (HEP) collaborations to deploy software on the worldwide-
distributed computing infrastructure used to run data processing applications.
CernVM-FS is implemented as a POSIX read-only file system in user space (a
FUSE module). Files and directories are hosted on standard web servers and
mounted in the universal namespace /cvmfs. Internally, CernVM-FS uses
content-addressable storage and Merkle trees in order to maintain file data
and meta-data. CernVM-FS uses outgoing HTTP connections only, thereby it
avoids most of the firewall issues of other network file systems. It transfers
data and meta-data on demand and verifies data integrity by cryptographic
hashes.
By means of aggressive caching and reduction of latency, CernVM-FS focuses specifically on the software use case. Software usually comprises many small files that are frequently opened and read as a whole. Furthermore, the software use case includes frequent look-ups for files in multiple directories when search paths are examined.
CernVM-FS is actively used by small and large HEP collaborations. In many cases, it replaces package managers and shared software areas on cluster file systems as means to distribute the software used to process experiment data.
.. toctree:: :maxdepth: 2 cpt-releasenotes cpt-overview cpt-quickstart cpt-configure cpt-squid cpt-repo cpt-servermeta cpt-replica cpt-repository-gateway cpt-notification-system part-advanced part-appendix
Visit our website on cernvm.cern.ch.
Authors of this documentation:
- Jakob Blomer
- Brian Bockelman
- Daniel-Florin Dosaru
- Dave Dykstra
- Nikola Hardi
- Nick Hazekamp
- René Meusel
- Radu Popescu