SUBMOUNT(8)

NAME
SUBMOUNT — automatically mounts and unmounts removable media devices.

SYNOPSIS

submount

A system for accessing removable media devices without manually remounting them between media changes.

DESCRIPTION

This manual page briefly documents the submount system.

Submount is a program that automatically mounts removable media devices or other filesystems when the mount directory is accessed, and unmounts them when they are no longer in use. It requires two parts: the subfs.o kernel module and the submountd program. Submountd should never be accessed directly by the user.

To invoke submount, use the mount(3) command, or edit the relevant entries in the fstab(5) file. Devices mounted to use submount should use subfs as the filesytem type, and add the option fs=< true filesystem > to the list of options.

eg. mount -t subfs /dev/scd0 /cdrom -o fs=iso9660,ro

To edit the fstab(5) file, one should also remove the "user", "owner" and "noauto" options. eg.

/dev/scd0 /cdrom udf:iso9660 ro,noauto,owner 0 0

becomes

/dev/scd0 /cdrom subfs fs=udf:iso9660,ro 0 0

The fs= can take an individual filesystem, a colon-seperated list of filesystems, which submountd will attmept to mount in the order in which they appear in the list, or a built-in list. As of version 0.5, the available lists are cdfss and floppyfss, which include the filesystems most commonly used on CD and floppy devices respectively. You may also use fs=auto, in which case, submountd will attempt to determine the filesystem by reading the device's superblock.

procuid can be added to the list of options if you wish to mount the filesystem with the UID and GID numbers of the calling process. This can be useful for some security strategies.

If you want to mount nfs or another network filesystem, use the alternative program net-submountd by adding program=/sbin/net-submountd to the list of options. The net-submountd program takes the option interval=XX where XX represents the time in seconds submount will wait between attempts to unmount the filesystem. If no value is give, net-submountd will default to a 15 second interval.

The net-submountd program is intended for use for simple network shares only, where editing /etc/auto.master and related files are a hassle rather than an opportunity to automate the configuration of many shares. For complex nfs setups automount is, and will continue to be the appropriate tool. An example with nfs(5):

192.168.1.12:/myshare /mnt/myshare nfs rsize=8192,....

becomes

192.168.1.12:/myshare /mnt/myshare subfs fs=nfs,program=/sbin/net-submount,....

SEE ALSO

mount(3), fstab(5), nfs(5).

Additional documentation may be found at http://submount.sourceforge.net

AUTHOR

This manual page was written by Eugene S. Weiss yossarian@users.sourceforge.net. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 2 any later version published by the Free Software Foundation.