Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
FS_MKMOUNT(1)		     AFS Command Reference		 FS_MKMOUNT(1)

       fs_mkmount - Creates a mount point for a	volume

       fs mkmount -dir <directory> -vol	<volume	name>
	   [-cell <cell	name>] [-rw] [-fast] [-help]

       fs mk -d	<directory> -v <volume name>
	   [-c <cell name>] [-r] [-f] [-h]

       The fs mkmount command creates a	mount point for	the volume named by
       the -vol	argument at the	location in the	AFS file space specified by
       the -dir	argument. The mount point looks	like a standard	directory
       element,	and serves as the volume's root	directory, but is actually a
       special file system object that refers to an AFS	volume.	When the Cache
       Manager first encounters	a given	mount point during pathname traversal,
       it contacts the VL Server to learn which	file server machines house the
       indicated volume, then fetches a	copy of	the volume's root directory
       from the	appropriate file server	machine.

       It is possible, although	not recommended, to create more	than one mount
       point to	a volume. The Cache Manager can	become confused	if a volume is
       mounted in two places along the same path through the filespace.

       The Cache Manager observes three	basic rules as it traverses the	AFS
       filespace and encounters	mount points:

       Rule 1: Access Backup and Read-only Volumes When	Specified
	   When	the Cache Manager encounters a mount point that	specifies a
	   volume with either a	".readonly" or a ".backup" extension, it
	   accesses that type of volume	only. If a mount point does not	have
	   either a ".backup" or ".readonly" extension,	the Cache Manager uses
	   Rules 2 and 3.

	   For example,	the Cache Manager never	accesses the read/write
	   version of a	volume if the mount point names	the backup version. If
	   the specified version is inaccessible, the Cache Manager reports an

       Rule 2: Follow the Read-only Path When Possible
	   If a	mount point resides in a read-only volume and the volume that
	   it references is replicated,	the Cache Manager attempts to access a
	   read-only copy of the volume; if the	referenced volume is not
	   replicated, the Cache Manager accesses the read/write copy. The
	   Cache Manager is thus said to prefer	a read-only path through the
	   filespace, accessing	read-only volumes when they are	available.

	   The Cache Manager starts on the read-only path in the first place
	   because it always accesses a	read-only copy of the root.afs volume
	   if it exists; the volume is mounted at the root of a	cell's AFS
	   filespace (named /afs by convention). That is, if the "root.afs"
	   volume is replicated, the Cache Manager attempts to access a	read-
	   only	copy of	it rather than the read/write copy. This rule then
	   keeps the Cache Manager on a	read-only path as long as each
	   successive volume is	replicated. The	implication is that both the
	   "root.afs" and "root.cell" volumes must be replicated for the Cache
	   Manager to access replicated	volumes	mounted	below them in the AFS
	   filespace. The volumes are conventionally mounted at	the /afs and
	   /afs/cellname directories, respectively.

       Rule 3: Once on a Read/write Path, Stay There
	   If a	mount point resides in a read/write volume and the volume name
	   does	not have a ".readonly" or a ".backup" extension, the Cache
	   Manager attempts to access only the read/write version of the
	   volume. The access attempt fails with an error if the read/write
	   version is inaccessible, even if a read-only	version	is accessible.
	   In this situation the Cache Manager is said to be on	a read/write
	   path	and cannot switch back to the read-only	path unless mount
	   point explicitly names a volume with	a ".readonly" extension.
	   (Cellular mount points are an important exception to	this rule, as
	   explained in	the following discussion.

       There are three types of	mount points, each appropriate for a different
       purpose because of the manner in	which the Cache	Manager	interprets

       o   When	the Cache Manager crosses a regular mount point, it obeys all
	   three of the	mount point traversal rules previously described. To
	   create a regular mount point, include only the required -dir	and
	   -vol	arguments to the fs mkmount command.

       o   When	the Cache Manager crosses a read/write mount point, it
	   attempts to access only the volume version named in the mount
	   point. If the volume	name is	the base (read/write) form, without a
	   ".readonly" or ".backup" extension, the Cache Manager accesses the
	   read/write version of the volume, even if it	is replicated. In
	   other words,	the Cache Manager disregards the second	mount point
	   traversal rule when crossing	a read/write mount point: it switches
	   to the read/write path through the filespace.

	   To create a read/write mount	point, include the -rw flag on the fs
	   mkmount command. It is conventional to create only one read/write
	   mount point in a cell's filespace, using it to mount	the cell's
	   "root.cell" volume just below the AFS filespace root	(by
	   convention, /afs/.cellname).	See the	OpenAFS	Quick Start Guide for
	   instructions	and the	chapter	about volume management	in the OpenAFS
	   Administration Guide	for further discussion.

	   Creating a read/write mount point for a read-only or	backup volume
	   is acceptable, but unnecessary. The first rule of mount point
	   traversal already specifies that the	Cache Manager accesses them if
	   the volume name in a	regular	mount point has	a ".readonly" or
	   ".backup" extension.

       o   When	the Cache Manager crosses a cellular mount point, it accesses
	   the indicated volume	in the specified cell, which is	normally a
	   foreign cell. (If the mount point does not name a cell along	with
	   the volume, the Cache Manager accesses the volume in	the cell where
	   the mount point resides.) The Cache Manager disregards the third
	   mount point traversal rule when crossing a regular cellular mount
	   point: it accesses a	read-only version of the volume	if it is
	   replicated, even if the volume that houses the mount	point is
	   read/write. Switching to the	read-only path in this way is designed
	   to avoid imposing undue load	on the file server machines in foreign

	   To create a regular cellular	mount point, include the -cell
	   argument on the fs mkmount command. It is conventional to create
	   cellular mount points only at the second level in a cell's
	   filespace, using them to mount foreign cells' root.cell volumes
	   just	below the AFS filespace	root (by convention, at
	   /afs/foreign_cellname). The mount point enables local users to
	   access the foreign cell's filespace,	assuming they have the
	   necessary permissions on the	ACL of the volume's root directory and
	   that	there is an entry for the foreign cell in each local client
	   machine's /usr/local/etc/openafs/CellServDB file. In	the output of
	   the fs lsmount command, the cell name and a colon (":") appear
	   between the initial number sign and the volume name in a regular
	   cellular mount point	name.

       -dir <directory>+
	   Names the directory to create as a mount point. The directory must
	   not already exist. Relative pathnames are interpreted with respect
	   to the current working directory.

	   Specify the read/write path to the directory, to avoid the failure
	   that	results	from attempting	to create a new	mount point in a read-
	   only	volume.	By convention, the read/write path is indicated	by
	   placing a period before the cell name at the	pathname's second
	   level (for example, /afs/ For further discussion of the
	   concept of read/write and read-only paths through the filespace,
	   see "DESCRIPTION".

       -vol <volume name>
	   Specifies the name or volume	ID number of the volume	to mount. If
	   appropriate,	add the	".readonly" or ".backup" extension to the
	   name, or specify the	appropriate volume ID number.

       -cell <cell name>
	   Names the cell in which the volume resides (creates a cellular
	   mount point). Provide the fully qualified domain name, or a
	   shortened form that disambiguates it	from the other cells listed in
	   the local /usr/local/etc/openafs/CellServDB file.

	   If this argument is omitted,	no cell	indicator appears in the mount
	   point. When the Cache Manager interprets it,	it assumes that	the
	   volume named	in the mount point resides in the same cell as the
	   volume that houses the mount	point.

       -rw Creates a read/write	mount point. Omit this flag to create a
	   regular mount point.

	   Prevents the	Volume Location	(VL) Server from checking that the
	   volume has a	VLDB entry and printing	a warning message if it	does
	   not.	Whether	or not this flag is included, the File Server creates
	   the mount point even	when the volume	has no VLDB entry.

	   Prints the online help for this command. All	other valid options
	   are ignored.

       The following command creates a regular mount point, mounting the
       volume "user.smith" at /afs/

	  % cd /afs/
	  % fs mkmount -dir smith -vol user.smith

       The following commands create a read/write mount	point and a regular
       mount point for the ABC Corporation cell's "root.cell" volume in	that
       cell's file tree. The second command follows the	convention of putting
       a period	at the beginning of the	read/write mount point's name.

	  % fs mkmount -dir /afs/ -vol root.cell
	  % fs mkmount -dir /afs/ -vol root.cell -rw

       The following command mounts the	State University cell's	"root.cell"
       volume in the ABC Corporation cell's file tree, creating	a regular
       cellular	mount point called /afs/ When a ABC Corporation
       Cache Manager encounters	this mount point, it crosses into the State
       University cell on a read-only path.

	  % fs mkmount -dir /afs/ -vol root.cell -c

       The issuer must have the	"i" (insert) and "a" (administer) permissions
       on the ACL of the directory that	is to house the	mount point.

       CellServDB(5), fs_lsmount(1), fs_rmmount(1)

       IBM Corporation 2000. <> All Rights Reserved.

       This documentation is covered by	the IBM	Public License Version 1.0.
       It was converted	from HTML to POD by software written by	Chas Williams
       and Russ	Allbery, based on work by Alf Wachsmann	and Elizabeth Cassell.

OpenAFS				  2016-12-14			 FS_MKMOUNT(1)


Want to link to this manual page? Use this URL:

home | help