Enhanced AutoFS Administrator's Guide

An Introduction to AutoFS
Overview of AutoFS
Chapter 1 3
Overview of AutoFS
AutoFS is a client-side service that supports automatic mounting and
unmounting of file systems. This process is nearly transparent to the
user.
AutoFS is implemented as a virtual file system (VFS). It supports
automounting by instructing the user-space daemon, automountd, to
mount and unmount the directories it manages. It automatically mounts
the appropriate file systems when needed and unmounts them if they
have been idle for the configured period of time (10 minutes is the default
value).
AutoFS has been enhanced to provide the features of the SUN ONC+
version 2.3 AutoFS product. This version of AutoFS is known as
Enhanced AutoFS. With the Enhanced AutoFS implementation, both
performance and scalability are significantly improved.
How AutoFS Works
AutoFS consists of the following components:
• The automount command – It installs AutoFS mount points and
associates an automount map with each mount point. The AutoFS
file system monitor attempts to access directories within it and
notifies the automountd daemon. The daemon uses the map to locate
a file system and then mounts this file system at the point of
reference within the AutoFS file system. The automount map
determines the location of all the AutoFS mount points.
NOTE You need to execute the automount command whenever the master
map or the direct maps are updated.
• The AutoFS file system (kernel AutoFS) – A virtual file system that
provides a directory structure for automatic mounting. It includes
autofskd, a kernel-based process that periodically cleans up mounts.
• The automountd daemon – A stateless daemon that accepts RPC
requests from kernel AutoFS to perform mounts or umounts.