The CernVM File System (CernVM-FS) is a read-only file system designed to deliver scientific software onto virtual machines and physical worker nodes in a fast, scalable, and reliable way. Files and file metadata are downloaded on demand and aggressively cached. (see also

CernVM-FS is a useful solution for ensuring access to commonly used datasets is centralised and easy, and the datasets are always updated on the main repository server (Stratum 0), mirrored by replica web servers (Stratum 1), fetched by the proxies (Stratum 2), and accessible to clients (Stratum 3).

CernVM-FS is used by the Galaxy project, as described on the Galaxy Training Network.