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FS_MKMOUNT(1) | AFS Command Reference | FS_MKMOUNT(1) |
NAME¶
fs_mkmount - Creates a mount point for a volumeSYNOPSIS¶
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]
DESCRIPTION¶
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.
- 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.
- 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.
- •
- 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.
- •
- 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 cells.
OPTIONS¶
- -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.
- -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.
- -rw
- Creates a read/write mount point. Omit this flag to create a regular mount point.
- -fast
- 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.
- -help
- Prints the online help for this command. All other valid options are ignored.
EXAMPLES¶
The following command creates a regular mount point, mounting the volume "user.smith" at /afs/abc.com/usr/smith:% cd /afs/abc.com/usr % fs mkmount -dir smith -vol user.smithThe 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/abc.com -vol root.cell % fs mkmount -dir /afs/.abc.com -vol root.cell -rwThe 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/stateu.edu. 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/stateu.edu -vol root.cell -c stateu.edu
PRIVILEGE REQUIRED¶
The issuer must have the "i" (insert) and "a" (administer) permissions on the ACL of the directory that is to house the mount point.SEE ALSO¶
CellServDB(5), fs_lsmount(1), fs_rmmount(1)COPYRIGHT¶
IBM Corporation 2000. <http://www.ibm.com/> 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.2014-06-12 | OpenAFS |