A read cache is a special read-only file system that stores copies of individual files outside of their local file systems, enabling a server or a node to have a cached copy of the file. When NFS v2 or NFS v3 clients submit a read request for a file in the read cache, the server or node can serve the read request from the copy in the read cache. Note that a read cache does not benefit CIFS clients, and that read caches have special characteristics and limitations.