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Introduction

The purpose of this module is to simplify mounting of local disks, remote file shares and virtual memory. Before a Unix system can access files on any hard disk, CDROM, Jaz drive, floppy disk or file server it must be mounted at some point in the filesystem. The system keeps a list of filesystems that it knows about, typically to mount at bootup time. Filesystems can also be mounted temporarily, to be forgotten about when they are unmounted or the system is rebooted.

All Unix systems when installed will mount at least one filesystem at bootup time, and almost certainly more. There will always be one filesystem mounted as the root directory /, and maybe others as /usr, /proc or /net. Unless your Unix system is a diskless workstation, the root directory will be mounted from a local hard disk. Others filesystems may be mounted from file servers, local disks or even be 'magic' filesystems like /proc that do not contain real files.

One special case is virtual memory. Your system should always have at least one virtual memory swap file, which is used by the OS as an extension of physical memory. A swap file can either be a normal file in some filesystem, or a dedicated partition on a local disk.

This module works by reading and updating the file /etc/fstab or /etc/vfstab to manage known filesystems. Currently mounted filesystems are found by reading the file /etc/mtab or /etc/mnttab. Webmin will totally ignore any comments in the known filesystems table.


Listing Current Filesystems

The main page of the Filesystem Manager module lists all the known filesystems. For each filesystem, the following details will be displayed :


Adding a New Filesystem

To add a new mount, choose the filesystem type from the selector below the list of existing mounts. This will display a form for entering the mount point, mount source and other options for the new mount. Each filesystem type for each Unix version has a different set of options, and many types have different possibilities for mount sources.

No matter what filesystem type you choose, some inputs will be the same on the Create Mount form. The most important is the mount point, which is the directory at which the filesystem is to be mounted. All filesystem types except virtual memory require you to enter this. If the directory you enter does not exist, Webmin will attempt to create it for you.

For most types of filesystem you will have 3 options for saving the mount :

For most filesystem types, you can also choose whether to mount now or not. Choosing not to mount or save a new filesystem is pointless, and will display an error.

There are however some types of filesystem which will not present all the options listed above. Some examples are :

All filesystem types require you to choose the mount source and mount options. Because the source and options differ significantly between different Unix flavours and filesystem types they are described individually in the list below :


Editing an Existing Filesystem

To edit an existing mount, click on the mount point from the list on the main page. This will display the form used for creating a new mount with the current mount point, source and options filled in. You can now change any of these on the form, in the same way as you would create a new mount (described above).

An existing mount will be either permanently saved, currently mounted or both. If you change the mount to be not saved or mounted, then it will be deleted from the mount list. Note that some filesystem types will not have both these options.

Under Unix a directory cannot be unmounted if it is currently in use, either by a process having a file in the directory open or by a user having some subdirectory as his current directory. Similarly, a swap file cannot be unmounted if the amount of free memory is less than the size of the swap file. When you change the directory, source or options of an existing mount, Webmin will unmount and remount it to apply the changes. This will fail if the directory or swap file is in use, and an error displayed.


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