automount Daemon

AIX Version 4.3 Commands Reference, Volume 1

automount Daemon

Mounts NFS file systems automatically.

Purpose

Mounts automatic mount points.

Syntax

/usr/sbin/automount [ -m ] [-n ] [ -T ] [ -v ] [ -D name=value ] [ -f MasterFile ] [ -M MountDirectory ] [ -tl Duration ] [ -tm Interval ] [ -tw Interval ] Directory ..$. MapName ... [ -MountOption [ ,MountOption ] ... ]

Description

Note: Some of the flags in the AIX 4.3.1 version of the automount command The syntax of the command line has changed in this implementation, some of the arguments are accepted but have no other purpose other than to maintain compatibility between the new AutoFS implementation of automatic mounting and the pre-AutoFS implementation.

The automount command is used as an administration tool for AutoFS. It installs AutoFS mount points and associates an automount map with each mount point. The AutoFS file system monitors attempts to access directories within it and notifies the automountd daemon. The daemon uses the map to locate a file system, which it then mounts at the point of reference within the AutoFS file system.

If the file system is not accessed within an appropriate interval (five minutes by default), the automountd daemon unmounts the file system.

The filename that contains the command line map information is /tmp/autofs_cmdline.

If the automountd daemon has not been started the automount command attempts to start it via SRC.

Maps

Updates to an map are transparent to the users because name-to-location binding is dynamic. This process eliminates the need to pre-mount shared file systems for applications containing hard-coded references to files.

See "How to Manage NIS automount Maps" in AIX Version 4.3 System Management Guide: Communications and Networks for more information about formatting map entries, multiple mounts, special maps, and the auto_master/auto.master NIS configuration map file.

The -MountOptions argument is a list of mount options. The list is preceded by a - (minus sign), and each option is separated by a comma. If this argument is supplied, the options usually become the default mount options for all entries in the map.

Notes:

Mount options provided in a map entry override the -MountOptions argument.
The mount command's bg background mount option is not recognized by the automount daemon.

The automount daemon is single-threaded. Any request delayed by a slow or unresponsive NFS server delays all subsequent automatic mount requests until the initial request completes. Programs that read the /etc/mtab file and then touch files that reside under automatic mount points introduce further entries to the file. Automatically mounted file systems are mounted with the mount command's -t type option set equal to ignore. These file systems do not appear in the output of either the mount command or the df command.

Environment Variables

Environment variables, specific only to the automount daemon, can be used in an automount map. When the daemon encounters an automount variable, the environment expands to account for the new variable. Environment variables are valid only for the automounter's environment, not for the operating system's environment.

References can be protected from affixed characters by enclosing the variable name in { } (curly braces).

Note: Some NFS servers support mount options not supported by the AIX: grpid, noauto, remount, quota, noquota, posix, nocto, and noac. By default, the AIX version of the automount daemon ignores these listed options. To reverse the effect of this default, use the AUTOMOUNT_BAD_OPTS shell environment variable.

Configuration

The automount daemon normally consults the auto.master NIS configuration map for a list of initial Directory-to-MapName pairs, and sets up automatic mounts for them in addition to those given on the command line. If there are duplications, the command-line parameters take precedence.

Note: This map contains the automount daemon parameter. The automount daemon does not look for an auto.master file on the local host.

See "How to Manage NIS automount Maps" in AIX Version 4.3 System Management Guide: Communications and Networks for more information about configuring the auto.master NIS map file.

Flags

-D envar=Value	Assigns a value to the indicated automount command environment variable.
-f MasterFile	Reads the named local file, rather than the master NIS map file, for initialization.
-m	Suppresses initialization of directory-mapname pairs listed in the master NIS database.
-M MountDirectory	This flag is ignored and only exixts for compatability reasons.
-n	This flag is ignored and only exixts for compatability reasons.
-T	Traces automount activity for diagnostic purposes, displaying it on standard output.
-tl Duration	Specifies a duration, in seconds, that a looked-up name remains cached when not in use. The default is 5 minutes.
-tm Interval	Specifies an interval in seconds, between attempts to mount a file system. The default is 30 seconds.
-tw Interval	Specifies an interval, in seconds, between attempts to unmount file systems that have exceeded their cached times. The default is 60 seconds.
-v	Displays on standard output verbose status and warning messages.

Files

/tmp_mount	Contains the directory under which file systems are dynamically mounted.
auto_master or auto.master	Contains the NIS configuration map for the automount daemon.

Related Information

The df command, mount command.

How to Manage NIS automount Maps in AIX Version 4.3 System Management Guide: Communications and Networks discusses map formatting, multiple mounts, special maps, and the auto.master NIS configuration map file.

List of NFS Commands.

Network File System (NFS) Overview for System Management in AIX Version 4.3 System Management Guide: Communications and Networks.