Creates a mount point for a fileset
Synopsis
fts crmount -dir directory_name {-fileset {name | ID} | -global} [-rw]
[-fast] [-help]
Options
-dir directory_name
Names the location in the file tree at which the root directory of the fileset is to be mounted. The specified location becomes the fileset's
mount point. The specified mount point must not already exist, but the parent directory of the mount point must exist in the DFS filespace.
-fileset {name | ID}
Specifies the complete name or fileset ID number of the fileset to be mounted. The mount point for the fileset is created at the location
specified with the -dir option. The read/write, read-only, or backup version of the fileset can be named. Use this option or use the -global option.
-global
Specifies that the mount point named with the -dir option is for the root of the DCE global namespace (a global root mount point). Use this option or use the
-fileset option. Do not use the -global option under normal circumstances; it is maintained to provide backward compatibility with other file systems (for example, AFS).
-rw
Specifies the type of the mount point as read/write. By default, a mount point is regular. If this option is used, the -fileset option must specify the read/write
version of the fileset.
An important function of the -rw option is to mount a cell's main read/write fileset, root.dfs, below the top-level of the cell's DFS filespace. The option must be used in this capacity at installation if replication is to be available in the cell. See Description for more information about the different types of mount points and about using the -rw option to create a read/write mount point for the fileset root.dfs.
-fast
Directs fts not to verify the existence of the fileset indicated with the -fileset option. Use this option to create a mount point for a fileset that
does not yet exist.
By default, fts contacts the Fileset Location (FL) Server for the cell that houses the parent directory of the name supplied with the -dir option to verify that the FLDB contains an entry for the fileset to be mounted. If no FLDB entry exists for the specified fileset, the command displays a warning. The specified mount point is always created, regardless of whether the -fast option is provided; the option simply suppresses the check and any possible warnings.
-help
Prints the online help for this command. All other valid options specified with this option are ignored.
Description
The fts crmount command creates a mount point for the fileset specified with the -fileset option at the location in the file tree specified with
the -dir option. The mount point makes the contents of the specified fileset visible and accessible to users. Once this command is used to mount a fileset, no further actions need to be
taken to mount the fileset and the fileset never needs to be mounted again.
A mount point is actually a special symbolic link that acts as an association between a directory location and a fileset. Mount points look and function like standard directories. When the Cache Manager encounters a mount point in a path name traversal, it determines which fileset is associated with the mount point. When it finds that fileset, it can access files or directories contained in the fileset's root directory. It traverses any paths leading through directories or other mount points in the fileset until it finds the directory or file indicated by the path name.
To a large extent, the type of a mount point determines the version of a fileset through which the Cache Manager searches for a requested directory or file. By default, every mount point created by the fts crmount command is a regular mount point, which is the most common type of mount point. However, if you include the -rw option with the command, the command creates a read/write mount point.
When the Cache Manager encounters a regular mount point, it checks the version of the fileset that the mount point indicates. If the mount point indicates the read-only or backup version of the fileset, the Cache Manager accesses that version. If the mount point indicates the read/write version of the fileset, the Cache Manager considers the fileset in which the mount point resides and acts accordingly, as follows:
· If a regular mount point that names a read/write fileset resides in a read-only fileset, the Cache Manager first determines whether the fileset is replicated. If the fileset is not replicated, the Cache Manager attempts to access the read/write version of the fileset; if the read/write version does not exist or is inaccessible, the Cache Manager cannot access the fileset. If the fileset is replicated, the Cache Manager attempts to access a read-only version of the fileset; if all of the read-only copies are unavailable, the Cache Manager cannot access the fileset (it does not attempt to access the read/write version of the fileset).
· If a regular mount point that names a read/write fileset resides in a read/write fileset, the Cache Manager attempts to access only the read/write version of the fileset. If the read/write version does not exist or is inaccessible, the Cache Manager cannot access the fileset.
When the Cache Manager encounters a read/write mount point, it attempts to access only the read/write version of the fileset, regardless of the type of fileset in which the mount point resides. If the read/write version of the fileset does not exist or is inaccessible, the Cache Manager cannot access the fileset.
Regular mount points promote greater fileset availability than read/write mount points because they allow the Cache Manager to access read-only filesets as often as possible. Because multiple copies of read-only filesets typically exist, regular mount points generally increase fileset availability. Conversely, because only a single version of a read/write fileset can exist, read/write mount points generally reduce fileset availability.
You typically mount filesets with regular mount points. A regular mount point is explicitly not a "read-only" mount point. Although the Cache Manager attempts to access a read-only version of a fileset when it encounters a regular mount point, it accesses the read/write version of the fileset if no read-only versions of the fileset exist or if it is traversing a read/write path (that is, if it accessed the mount point in a read/write fileset).
During a cell's configuration, an important function of the fts crmount command is to create a mount point for the cell's main read/write fileset, root.dfs. The command must be used with the -rw option to create an explicit read/write mount point for the fileset below the top-level of the cell's DFS filespace. The mount point for the fileset must be created at /.../cellname/fs/.rw.
The root.dfs fileset is the first fileset mounted in a cell. The Cache Manager automatically mounts it at the top-level of the cell's DFS filespace (/.../cellname/fs by default, but it can be defined as something else). It must be created as a DCE LFS fileset with the fts create command if functionality such as replication is to be available in the cell.
Once the root.dfs fileset is mounted with a read/write mount point, it can be replicated. Replication is then available for DCE LFS filesets in the cell. If root.dfs is replicated before its read/write mount point is created with the fts crmount command, the read/write version of root.dfs cannot be accessed in the cell. Part 1 of the OSF DCE DFS Administration Guide and Reference provides information about configuring root.dfs to support replication.
Privilege Required
If the parent directory of the mount point (the directory in which the mount point is to be created) is in a DCE LFS fileset, the issuer must have write,
execute, control, and insert permissions on the directory. If the parent directory is in a non-LFS fileset, the issuer must have write and execute permissions on the directory.
Cautions
Do not mount a fileset at more than one location in the file system. Creating multiple mount points can distort the hierarchical nature of the file system. Because
the Cache Manager stores only a single pointer to the parent directory of the mount point for each fileset, it can become confused about which path name to follow when searching for a file in a
fileset with multiple mount points. This is true even if the full path name of a file is specified.
Create multiple mount points for a fileset sparingly, only in a very limited number of troubleshooting and testing situations. Remove the extraneous mount points as soon as they are no longer necessary.
Do not create a symbolic link that begins with a # (number sign) or a % (percent sign) character. Because a mount point is a special type of symbolic link that uses these characters internally to identify its type, the Cache Manager becomes confused if it encounters a normal symbolic link that begins with one of these characters.
Examples
The following command creates a regular mount point (the default type of mount point) for the read/write fileset named user.jlw at the directory named
/.../abc.com/fs/usr/jlw:
$ fts crmount /.../abc.com/fs/usr/jlw user.jlw
The following command creates a read/write mount point for the fileset named root.dfs in the cell abc.com. The fileset is mounted at .rw, immediately below the top-level of the cell's DFS filespace.
$ fts crmount /.../abc.com/fs/.rw root.dfs -rw
Related Information
Commands: dfsd(8dfs)