FS-Cache is a kernel facility by which a network filesystem or other service can cache data locally, trading disk space to gain performance improvements for access to slow networks and media. It can be used by any filesystem that wishes to use it, for example AFS, NFS, CIFS, and ISOFS. It can support a variety of backends: different types of cache that have different trade-offs.
FS-Cache is designed to impose as little overhead and as few restrictions as possible on the client network filesystem using it, whilst still providing the essential services.
The presence of a cache indirectly improves performance of the network and the server by reducing the need to go to the network.