ONC Services Overview

Network File System (NFS) enables you to access files from any location on the network, transparently. An NFS server makes a directory available to other hosts on the network, by sharing the directory. An NFS client accesses the shared directories on the NFS server by mounting the directories. For users on the NFS client, the directories appear as a part of the local filesystem. For information on configuring and administering NFS, see Chapter 2 “Configuring and Administering NFS Services”.

AutoFS is a client-side service that automatically mounts and unmounts filesystems, transparently. AutoFS performs automatic mounting and unmounting by instructing the user-space daemon, automountd, to mount and unmount the directories it manages. For information on configuring and administering AutoFS, see Chapter 3 “Configuring and Administering AutoFS”.

CacheFS is a general purpose filesystem caching mechanism that can improve the NFS server performance scalability by reducing server and network load. For information on configuring and administering a cache filesystem, see Chapter 4 “Configuring and Administering a Cache Filesystem”.

Network Lock Manager (NLM) and Network Status Monitor (rpc.lockd and rpc.statd) provide file locking and synchronized file access to files that are shared using NFSv2 or NFSv3. File locking with NFSv2 and NFSv3 is advisory only. The rpc.lockd daemon starts the kernel KLM server. The rpc.statd daemon implements a lock recovery service used by KLM. It enables rpc.lockd daemon to recover locks after the NFS service restarts.

Files can be locked using the lockf() or fcntl() system calls. For more information on daemons and system calls that enable you to lock and synchronize your files, see lockd(1M), statd(1M), lockf(2), and fcntl(2).

Remote Procedure Call (RPC) is a mechanism that enables a client application to communicate with a server application. The NFS protocol uses RPC to communicate between NFS clients and NFS servers. You can write your own RPC applications using rpcgen, an RPC compiler that simplifies RPC programming. Transport-Independent RPC (TI-RPC) is supported on HP-UX 11i v3. For information on RPC, see rpc(3N) and rpcgen(1). For more information on RPC and rpcgen, see John Bloomer, Power Programming with RPC.