Mounting File Systems

You can mount file systems in several ways. They can be mounted automatically when the system is booted, on demand from the command line, or through the automounter. The automounter provides many advantages to mounting at boot time or mounting from the command line, but many situations require a combination of all three.

How to Mount at Boot Time

If you want to mount file systems at boot time instead of using autofs maps, follow this procedure. Although you must follow this procedure for all local file systems, it is not recommended for remote file systems because it must be completed on every client.

Edit the /etc/vfstab file.

Entries in the /etc/vfstab file have the following syntax:

special  fsckdev  mountp  fstype  fsckpass  mount-at-boot  mntopts

Example of a vfstab entry

You want a client computer to mount the /var/mail directory from the server wasp. You would like the file system to be mounted as /var/mail on the client and you want the client to have read-write access. Add the following entry to the client's vfstab file.

wasp:/var/mail - /var/mail nfs - yes rw

NFS servers should not have NFS vfstab entries because of a potential deadlock. The NFS service is started after the entries in /etc/vfstab are checked, so that if two servers that are mounting file systems from each other fail at the same time, each system could hang as the systems reboot.

How to Mount From the Command Line

To mount a file system manually during normal operation, run the mount command as superuser:

# mount -F nfs -o ro bee:/export/share/local /mnt

In this case, the /export/share/local file system from the server bee is mounted on read-only /mnt on the local system. Mounting from the command line allows for temporary viewing of the file system. You can unmount the file system with umount or by rebooting the local host.

Starting with the 2.6 release, all versions of the mount command will not warn about invalid options. The command silently ignores any options that cannot be interpreted. Make sure you verify all of the options that were used, to prevent unexpected behavior.

How to Mount With the Automounter

Chapter 5, About Autofs includes the specific instructions for establishing and supporting mounts with the automounter. Without any changes to the generic system, clients should be able to access remote file systems through the /net mount point. To mount the /export/share/local file system from the previous example, all you need to do is type:

% cd /net/bee/export/share/local

Because the automounter allows all users to mount file systems, root access is not required. It also provides for automatic unmounting of file systems, so there is no need to unmount file systems after you are finished.