If you want to improve the performance and scalability of an NFS or CD-ROM file system, you should use the Cache File System (CacheFS). CacheFS is a general purpose file system caching mechanism that improves NFS server performance and scalability by reducing server and network load.
Designed as a layered file system, CacheFS provides the ability to cache one file system on another. In an NFS environment, CacheFS increases the client per server ratio, reduces server and network loads, and improves performance for clients on slow links, such as Point-to-Point Protocol (PPP). You can also combine CacheFS with the AutoFS service to help boost performance and scalability.
See Chapter 37, The Cache File System (Tasks) for detailed information about CacheFS.