After exporting, a remote client can view the exported file systems PROJ2 and PROJ3.
Not all the file systems on the server are visible to remote clients. Only the exported
file systems are available for mounting by clients with proper authorities as specified
on the export command or in the /etc/exports file. Remote clients can not see
anything except for their own local files and those that the various remote servers
have exported. Before remote clients can access server data, that data must first be
exported and then mounted.
How Do I Export File Systems?
Youcan export NFS server file systems for mounting on a client with the
CHGNFSEXP (Change Network File System Export) or the EXPORTFS CL
commands.
For a discussion of specific special considerations regarding export procedures,
please see “Chapter 9. Network File System Security Considerations”on page 81.
Rules for Exporting File Systems
There are four conceptual rules that apply when exporting the file systems of an
NFS server so that they are accessible to clients:
1. Any file system, or proper subset of a file system, can only be exported from a
system that runs NFS. Aproper subset of a file system is defined as a file or
directory that starts below the path of the file system being exported. This
capability allows you to export only certain parts of large file systems at any one
time instead of the entire file system all at once.
For example, /usr is a file system, and the /usr/public_html directory is part of
that file system. Therefore, /usr/public_html (and all of the objects, files, and
sub-directories located within that directory) is a proper subset of the /usr file
system.
Youmight want to think of the exporting process as you would think of a river.
When you throw an object into a river, it flows downstream. When you export a
file system, you also export all of the “downstream” directories, file systems, and
other objects. Just as rivers flow from upstream to downstream, so do your
exports.
Figure 20.After the server has exported /classes/class2
28 OS/400 Network File System Support V4R4