CernVM-FS is a web-based, global, and versioning file system optimized for software distribution.  The file system content is installed on a central web server from where it can be mirrored and cached by other web servers and web proxies.  File system clients download data and meta-data on demand and cache them locally.  Data integrity and authenticity is ensured by cryptographic hashes and digital signatures.  CernVM-FS is used, among others, by the LHC experiments for the distribution of 100 million files and directories of LHC experiment software onto tens of thousands of nodes distributed worldwide.

Advantages & Applications


Large-scale computing, big data processing.


  • Various Linux distributions (x86, AMD64, ARM) & Mac OS X (client) supported.
  • Global-scale open source file system optimized for software distribution.
  • Data transport via standard HTTP protocol.
  • Data integrity secured by cryptographic hashes and digital signatures.
  • File system level versioning.
  • Data de-duplication.
  • Transparent data compression/decompression and file chunking.
  • Capability to hot patch the file system client.
  • Capability to work in offline mode providing that all required files are cached.
  • Possibility to use Amazon Simple Storage Service (S3) compatible storage as a data backend.