Information Technology Reference
In-Depth Information
Introduction
This chapter covers some final topics relating to file systems. The first part
covers the Network File System (NFS) and the commands used to adminis-
ter NFS. The second part of the chapter describes the AutoFS and CacheFS
services that support NFS.
The NFS Environment
The
Network File System
(
NFS
) service uses the client/server model to allow
systems to remotely access the storage of other systems. The NFS protocol
is defined by Request For Comment (RFC) 1813, NFS Version 3 Protocol
Specification.
An NFS server allows computers of different architectures running different
operating systems to access its storage space across a network. The NFS
service also allows multiple systems to access the same information, elimi-
nating redundancy, improving consistency, and reducing administration.
An NFS client accesses this information in a somewhat transparent mode.
That is, the remote resource appears and can be treated as local storage space
for most operations and applications.
NFS Administration
Before file systems or directories can be accessed (that is, mounted) by a
client through NFS, they must be
shared
or, in older terminology,
advertised
.
Once shared, authorized NFS clients can mount the resources.
Another term used for sharing NFS resources is
exporting
. This term appears occa-
sionally in Solaris documentation but is most often seen as a directory name for NFS
resources such as
/export/home
or
/export/swap
.
Sharing NFS Resources
NFS resources can be shared using the
share(1M)
command and unshared
using the
unshare(1M)
command. In addition, any resources identified in the
/etc/dfs/dfstab
file are automatically shared at system boot or when the
shareall(1M)
command is used. Shared resources are automatically recorded
in the
/etc/dfs/sharetab
file. When the
unshareall(1M)
command is used, all
resources listed in the
/etc/dfs/sharetab
file are automatically unshared.
