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NAME | SYNOPSIS | INTRODUCTION | DESCRIPTION | EXAMPLES | FILES | SEE ALSO | AUTHOR | COLOPHON |
NFSREF(8) System Manager's Manual NFSREF(8)
nfsref - manage NFS referrals
nfsref [-?d] [-t type] add pathname server export [ server export ...
]
nfsref [-?d] [-t type] remove pathname
nfsref [-?d] [-t type] lookup pathname
NFS version 4 introduces the concept of file system referrals to NFS.
A file system referral is like a symbolic link on a file server to
another file system share, possibly on another file server. On an
NFS client, a referral behaves like an automounted directory. The
client, under the server's direction, mounts a new NFS export
automatically when an application first accesses that directory.
Referrals are typically used to construct a single file name space
across multiple file servers. Because file servers control the shape
of the name space, no client configuration is required, and all
clients see the same referral information.
The Linux NFS server supports NFS version 4 referrals.
Administrators can specify the refer= export option in /etc/exports
to configure a list of exports from which the client can choose. See
exports(5) for details.
The nfsref(8) command is a simple way to get started managing
junction metadata. Other administrative commands provide richer
access to junction information.
Subcommands
Valid nfsref(8) subcommands are:
add Adds junction information to the directory named by pathname.
The named directory must already exist, and must not already
contain junction information. Regular directory contents are
obscured to NFS clients by this operation.
A list of one or more file server and export path pairs is
also specified on the command line. When creating an NFS
basic junction, this list is stored in an extended attribute
of the directory.
If junction creation is successful, the nfsref(8) command
flushes the kernel's export cache to remove previously cached
junction information.
remove Removes junction information from the directory named by
pathname. The named directory must exist, and must contain
junction information. Regular directory contents are made
visible to NFS clients again by this operation.
If junction deletion is successful, the nfsref(8) command
flushes the kernel's export cache to remove previously cached
junction information.
lookup Displays junction information stored in the directory named by
pathname. The named directory must exist, and must contain
junction information.
When looking up an NFS basic junction, the junction
information in the directory is listed on stdout.
Command line options
-d, --debug
Enables debugging messages during operation.
-t, --type=junction-type
Specifies the junction type for the operation. Valid values
for junction-type are nfs-basic or nfs-fedfs.
For the add subcommand, the default value if this option is
not specified is nfs-basic. For the remove and lookup
subcommands, the --type option is not required. The nfsref(8)
command operates on whatever junction contents are available.
Suppose you have two file servers, top.example.net and
home.example.net. You want all your clients to mount
top.example.net:/ and then see the files under home.example.net:/
automatically in top:/home.
On top.example.net, you might issue this command as root:
# mkdir /home
# nfsref --type=nfs-basic add /home home.example.net /
Created junction /home.
/etc/exports
NFS server export table
exports(5)
RFC 5661 for a description of NFS version 4 referrals
Chuck Lever <chuck.lever@oracle.com>
This page is part of the nfs-utils (NFS utilities) project.
Information about the project can be found at
⟨http://linux-nfs.org/wiki/index.php/Main_Page⟩. If you have a bug
report for this manual page, see
⟨http://linux-nfs.org/wiki/index.php/Main_Page⟩. This page was
obtained from the project's upstream Git repository
⟨http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=summary⟩ on
2020-08-13. (At that time, the date of the most recent commit that
was found in the repository was 2020-08-07.) If you discover any
rendering problems in this HTML version of the page, or you believe
there is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
9 Jan 2018 NFSREF(8)
Pages that refer to this page: nfsref(8)