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       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 a 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

       ·   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.

       ·   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 IBM AFS Quick Beginnings for
           instructions and the chapter about volume management in the IBM AFS
           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.

       ·   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 /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 /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.