The CNF fileservers run OpenAFS (just AFS for short).
AFS (Andrew File System or A File System) is a distributed file system. The top directory of the AFS hierarchy is the same all over the world, and is /afs.
Every institution in the world with AFS fileservers has its own unique "cell" subdirectory under /afs. CNF's cell is named "cnf.cornell.edu" and is located at /afs/cnf.cornell.edu
Within a cell, files are located on fileservers and are grouped within entities named volumes. Volumes are partitions of physical disks (of the data servers), in which quotas are applied. Backups of data can also be performend on a per-volume basis. And, data on readonly volumes can be replicated across multiple fileservers.