Technical data

NFS Server
20.1 Key Concepts
You might use a container file system if:
• You do not require extensive file sharing between your OpenVMS system and
a UNIX client.
• Client applications require symbolic or hard links or special files.
20.1.2.2 Understanding the Container File System
The NFS software lets you create a logical UNIX style file system on your
OpenVMS host that conforms to UNIX file system rules. This means that any
UNIX application that accesses this file system continues to work as if it were
accessing files on a UNIX host.
An OpenVMS server can support multiple container file systems. Creating a
container file system is comparable to initializing a new disk with an OpenVMS
volume structure, because it provides the structure that enables users to create
files. The file system parameters, directory structure, UNIX style file names, and
file attributes are catalogued in a data file called a container file.
The number of UNIX containers you should create depends on how you want to
manage your system.
In a container file system, each conventional UNIX file is stored as a separate
data file. The container file also stores a representation of the UNIX style
directory hierarchy and, for each file name, a pointer to the data file. In addition
to its UNIX style name, each file in the container file system has a system-
assigned valid Files–11 file name.
An OpenVMS directory exists for each UNIX directory stored in the container.
All files catalogued in a UNIX directory are also catalogued in the corresponding
OpenVMS directory; however, the UNIX directory hierarchy is not duplicated in
the OpenVMS directory hierarchy.
Because each UNIX style file is represented as an OpenVMS data file, OpenVMS
utilities such as BACKUP can use standard access methods to access these files.
Note
Except for backing up and restoring files, you should not use DCL
commands to manipulate files in a container file system. Instead, use
the commands described in Section 20.10.
For more information about backing up and restoring files, see Section 20.7 and
Section 20.10.7.
For information about setting up container file systems, see Section 20.9.
20.1.3 How the Server Grants Access to Users and Hosts
The server uses the following database files to grant access to users on client
hosts:
• The export database, TCPIP$EXPORT.DAT, is a collection of entries used to
store information about the file systems you want to make available to users
on client hosts.
NFS Server 20–3