``Configuring the Network File System (NFS)'', explains how to mount remote filesystems on an NFS client using the conventional NFS mounting approach whose major characteristics are:
automount provides an alternative approach that mounts filesystems automatically, but not until they are needed.
Filesystem mounting: conventional vs. automount
|Conventional method||automount method|
|Mounts occur automatically and transparently at boot time or manually thereafter.||Mounts occur automatically and transparently when a user tries to access any files or directories under the designated mount point of the remote filesystem to be mounted.|
|Mounts must be removed manually, or during system reboot.||Mounts are removed automatically when the contents of the mounted filesystem have not been used for a specified period of time.|
|To manually access mounts, users must use the mount and umount commands. (In both conventional and automount methods, all user mounts must be preconfigured by the system administrator).||Users have transparent mount access; the mounts are automatically triggered when the user uses a command like cd to access files or directories that are actually on a remote filesystem. (In both conventional and automount methods, all user mounts must be preconfigured by the system administrator).|
|New links can be added at any time by the system administrator.||New links cannot be manually added and made active without rebooting automount.|
|Only one NFS server may be designated as the source of a filesystem, so mounts fail if that server is unavailable.||One or more NFS servers may be designated as the source of a filesystem. This redundancy means that if one server is unavailable, the mount may be obtained from another.|
|Service is primarily provided by the mount(ADM) and umount commands.||Service primarily provided by the automount(NADM) command.|
|Files used are /etc/default/filesys for configuring automatic mounts at boot time; /etc/mnttab for a listing of all the currently mounted filesystems.||Files used are a variety of maps for configuring automatic mounts; /etc/mnttab for a listing of all the currently mounted filesystems. (see ``The mount table'' for more information).|
In summary, the benefits of automount are:
Therefore, if you know you will regularly need to add new mounts, you may want to consider the relative benefits and drawbacks of both systems for your needs.