
This help page is incomplete
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 :
- Save and mount at boot
The mount will be recorded permanently, and mounted at bootup
time when the system is started.
- Save
The mount will be permanent, but not mounted at boot time.
- Don't save
The mount will only be temporary.
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 :
- Virtual Memory under Linux
Whenever this type is mounted it is saved, and whenever it is
unmounted it is deleted. Saved VM mounts are always added at
bootup time.
- Windows Networking under Linux
This filesystem type can only be mounted using the
smbmount command, so cannot be saved.
- Automounter Filesystems
Permanent Automounter filesystems are always mounted at boot
time.
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 :
- Redhat Linux 4.0+ and Slackware Linux 3.0+
For most Linux filesystem types, the mount source can be
one of the following :
- IDE device
For this choice you must enter the IDE device letter
and partition. The device letter is typically a
for the 1st internal hard disk, b for the 2nd
internal disk, and c for the CD-ROM. The
partition number depends on which partition you want
to mount. Use the fdisk command to see the
available partitionson your disks.
- SCSI device
For this option you must enter the SCSI device letter
and partition. The device letter does NOT correspond
to the SCSI target number - each SCSI device is assigned
a letter by Linux in the order they are found by the OS.
- Floppy disk
This choice only requires you to enter the floppy device
number. This will be 0 for your primary drive
or 1 for the secondary.
- Other device
If you choose this option, you can type in any device
pathname that you want to mount. This is useful for
mounting other RAOD devices, PCMCIA cards and other paths
that Webmin doesn't know about.
Before a filesystem on a local IDE or SCSI disk partition
can be mounted, the partition must have been created and a
filesystem built on it. The Partition
Manager module can be used to do this, or you can use
the Linux fdisk and mkfs commands.
The Network Filesystem (nfs), Windows Networking
Filesystem (smbfs), Automounter Filesystem (auto)
and Virtual Memory (swap) mount types use a different
form for the mount source. See the section about that filesystem
type below for more details.
Once you have chosen the mount source, you can also set various
filesystem-specific options. Some options however are common
to almost all Linux filesystems. They are :
Read-only |
If yes, then nobody can write, create, delete or change
anything on this filesystem |
Allow SUID files |
If no, then setuid programs on this filesystem will not
be run as their owner. Useful when mounting remote filesystems
that you don't trust |
The filesystem-specific options are :
- Linux Native Filesystem (ext2fs)
This is the latest filesystem type for local hard
disks on Linux.
The following additional options are available :
- Network Filesystem (nfs)
NFS is the standard Unix way of sharing files between
systems. For NFS, the mount source is not a local disk
but instead a hostname and remote directory. The hostname
is the name (or IP address) of the system you want to
mount from. The remote directory is a directory on the
remote system that is exported to your system.
NFS filesystems have the following additional options :
NFS version |
The version of NFS (1-3) to use |
- Virtual Memory (swap)
The mount source for virtual memory can be a local IDE
disk, SCSI disk or normal file. If you enter a filename
that does not exist, Webmin will ask for the size of
the swap file to create and then add it as swap.
Unless your Linux
kernel has been configured to allow it, a swap cannot be
on an NFS mounted filesystem.
There are no options for virtual memory mounts.
- Windows Networking Filesystem (smbfs)
Windows networking refers to the file sharing protocol
used by Samba, Windows 95 and NT (also known as SMB
or LANManager). If a Windows fileserver is sharing a
directory, you can mount it under Linux and access the
contents as normal files.
The mount source for a Windows networking filesystem
is a share name like \\ntbox\somedir. The first
part is the NetBIOS name of the server, and the second
the name of a share on the server. Ideally a server's
NetBIOS name should be the same as its TCP/IP hostname,
but if not you can use the mount options to specify
the correct hostname or IP address to connect to.
The following options are available :
Username |
The username to login to the fileserver with. Not
needed for public shares |
Password |
The password used with the username. If you do not
have a valid username and password on the server then the
mount will fail. Not needed for public shares |
- MS-DOS Filesystem (fat)
Floppy or hard disks formatted under Windows 3.1 and
versions of MS-DOS before 7.0 use this filesystem type.
Files in this filesystem are limited to the 8.3 filename
standard used by DOS. If you try to create a file with
a longer name, it will be truncated to the 8.3 format.
Because DOS has no concept of file ownership or real
file permissions, all files in the mounted directory
will have the same owner and access mode. The ownership
or rights of individual files cannot be changed.
The following options are available :
- Windows 95 Filesystem (vfat)
This filesystem is found on disks formatted by Windows 95
and possibly NT. Like the MS-DOS filesystem above it has
no concept of file ownership or permissions. However, it
can support long filenames.
Available options are :
- ISO9660 Filesystem (iso9660)
This is the standard format for CD-ROMs. The basic format
only supports 8.3 filenames like fat, but there
is an extended format called Rock Ridge that allows
files to have long names and Unix permissions.
The options for this filesystem are :
- OS/2 Filesystem (hpfs)
Hard disks formatted by OS/2 use this filesystem format.
Long filenames are supported, but Unix permissions and
file ownership are not.
Available options are :
- Linux on MS-DOS Filesystem (umsdos)
This filesystem is used only for installing Linux
on a system has only an MS-DOS filesystem, and cannot
be re-partitioned. It works by using the directory
\linux on the DOS filesystem as the root for the
Linux filesystem. When mounted under Linux, long
filenames, file ownership and permissions are supported.
This filesystem is not supported by default in
RedHat Linux, and should only be used if you have no
other option as performance is poor.
The valid options for umsdos are :
- Solaris 2.5+
For disk-based Solaris filesystems, the mount source can
be one of :
- SCSI Disk
Under Solaris, every SCSI disk is identified
by 4 numbers:
- Controller - The SCSI controller the
disk is connected to. Always 0 for the built-in
controller on Sparc boxes.
- Target - The SCSI unit number. For
internal hard drives this is 0 or 1. For
external drives it is typically settable by
a selector on the drive box.
- Unit - Almost always 0.
- Partition - The number of the partition
to mount.
- MetaDisk Device
If you have striped, mirrored or RAIDed devices
created using Sun's Metadevice software, choose
this option and enter the Metadevice number.
- Other Device
This choice requires you to enter the full path
to the device file to mount.
Before a filesystem on a local SCSI disk can be mounted,
the partition must be setup and a filesystem built on it.
The Partition Manager module can be
used to do this, or you can use the format and
newfs Unix commands.
Under Solaris, CDROMs and floppy disks are mounted automatically
by the volume manager. Unless this has been disabled, floppies
and CDROMs never need to be manually mounted. Devices mounted
by the volume manager are not displayed in the list of mounted
filesystems on the main page. This may also apply to removable
SCSI devices (such a Jaz or Syquest drives), depending on
how volume management is set up on your system.
Once the filesystem mount source has been chosen, you can also
set a number of filesystem-specific options :
- Solaris Unix Filesystem (ufs)
This is the standard filesystem type used by Solaris
for local disks.
The available options are :
Read-only |
If yes, then nobody can write, create, delete or
chmod anything on this filesystem |
- Network Filesystem (nfs)
NFS is the standard Unix way of sharing files between
systems. For NFS, the mount source is not a local disk
but instead a hostname and remote directory. The hostname
is the name (or IP address) of the system you want to
mount from. The remote directory is a directory on the
remote system that is exported to your system.
NFS filesystems have the following additional options :
- Virtual Memory (swap)
The mount source for virtual memory can be a SCSI disk,
MetaDisk device or normal file. If you enter a filename
that does not exist, Webmin will ask you for the size of
the swap file to create. Once the file is created, it
will be mounted as swap.
There are no options for Virtual Memory mounts.
- Caching Filesystem (cachefs)
This filesystem uses space on a local disk to cache
files from another filesystem, typically NFS. This
means that commonly accessed files from an NFS server
are kept locally, resulting in a significant speedup.
When you create a new Caching Filesystem mount, Webmin
assumes that the back filesystem is of type NFS.
The mount source for cachefs filesystems is the
NFS server and directory to cache. ???
When you mount a Caching filesystem, two mounts are
really made - the back mount and the cachefs
mount on the actual directory. Webmin does not show back
mounts on the list of mounted filesystems.
cachefs uses a cache directory to store
cached files, specified in the mount options. You can
either use the cfsadmin Unix command to create
a cache directory with the parameters you want, or let
Webmin set it up automatically. In the latter case, the
cache will be limit to 10% of the size of the filesystem
it is on.
Valid options for this filesystem are:
- Ram Disk Filesystem (tmpfs)
Files stored in a filesystem of this type exist only
in RAM, and are lost when unmounted or the system is
rebooted. The /tmp directory in Solaris uses
this filesystem type. Because it is stored only in
memory, there is no mount source section of the
filesystem form.
The only option is :
- Automounter Filesystem (autofs)
The Automounter does automatic mounting and unmounting
of NFS directories on demand. A subdirectory under an
automounter directory will come into existance and
mount a file server when the user first refers to it,
such as by cd'ing into the subdirectory. After some idle
time, the subdirectory will be unmounted an disappear.
The mount source for filesystems of this type has 3
different options :
- All NFS Servers (-net)
When the user cd's into a subdirectory, it is
taken as the hostname of an NFS server. If
this server exists, all the available exports
from the server will be mounted under the
new subdirectory.
Solaris by default has the /net
directory mounted with this source, so a user
can do something like
cd /net/bar.foo.com/usr/local/bin
ls -l
- XFN Server (-xfn)
No idea???
- Automounter map
For this option, the name of an NIS map or
local file containing an automounter map
must be given. The configuration of which
servers and directories to mount is specified
in this map. For more information, see the
automount man page.
The options for automounter filesystems are the same
as those for NFS. These options apply to the automatically
mounted subdirectories inside the automount directory.
- MS-DOS Filesystem (pcfs)
Disks formatted under MS-DOS use this filesystem. Files
in are limited to 8.3 filenames, and have no Unix
ownership or permissions. Typically, you will never
need to use Webmin to mount pcfs filesystem
floppy, as they are handled automatically by the volume
management system.
The options available for MS-DOS filesystems are :
- CDROM Filesystem (hsfs)
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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