System information
9.3.1. Mount ing NFS File Syst ems using /etc/fstab
An alternate way to mount an NFS share from another machine is to add a line to the /etc/fstab
file. The line must state the hostname of the NFS server, the directory on the server being exported,
and the directory on the local machine where the NFS share is to be mounted. You must be root to
modify the /etc/fstab file.
Examp le 9 .1. Syn t ax examp le
The general syntax for the line in /etc/fstab is as follows:
server:/usr/local/pub /pub nfs defaults 0 0
The mount point /pub must exist on the client machine before this command can be executed. After
adding this line to /etc/fstab on the client system, use the command mo unt /pub, and the mount
point /pub is mounted from the server.
The /etc/fstab file is referenced by the netfs service at boot time, so lines referencing NFS shares
have the same effect as manually typing the mo unt command during the boot process.
A valid /etc/fstab entry to mount an NFS export should contain the following information:
server:/remote/export /local/directory nfs options 0 0
The variables server, /remote/export, /local/directory, and options are the same ones used when
manually mounting an NFS share. Refer to Section 9.3, “ NFS Client Configuration” for a definition of
each variable.
Note
The mount point /local/directory must exist on the client before /etc/fstab is read. Otherwise,
the mount will fail.
For more information about /etc/fstab, refer to man fstab.
9.4. auto fs
One drawback to using /etc/fstab is that, regardless of how infrequently a user accesses the NFS
mounted file system, the system must dedicate resources to keep the mounted file system in place.
This is not a problem with one or two mounts, but when the system is maintaining mounts to many
systems at one time, overall system performance can be affected. An alternative to /etc/fstab is to
use the kernel-based auto mo unt utility. An automounter consists of two components:
a kernel module that implements a file system, and
a user-space daemon that performs all of the other functions.
The auto mo unt utility can mount and unmount NFS file systems automatically (on-demand
mounting), therefore saving system resources. It can be used to mount other file systems including
AFS, SMBFS, CIFS, and local file systems.
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