1MOUNT.FEDFS(8) System Manager's Manual MOUNT.FEDFS(8)
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7 mount.fedfs - mount a FedFS domain root
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10 mount.fedfs remotedir localdir [-fhnrsvVw] [-o options]
11
13 RFC 5716 introduces the Federated File System (FedFS, for short).
14 FedFS is an extensible standardized mechanism by which system adminis‐
15 trators construct a coherent namespace across multiple file servers
16 using file system referrals. For further details, see fedfs(7).
17 The mount.fedfs(8) command locates FedFS domains by looking for DNS SRV
19 records that advertise file servers exporting FedFS domain root repli‐
20 cas. The remotedir argument determines what FedFS domain is mounted
21 and what network file system protocol is used.
22 The mount.fedfs(8) command sorts the list of available domain root
24 replicas according to the SRV record sorting rules outlined in RFC
25 2782. It attempts to contact each file server appearing in the SRV
26 record list until a mount request succeeds or the end of the SRV record
27 list is reached.
28 Command line arguments
30 The first argument, remotedir, is the globally useful name to mount.
31 Globally useful names are discussed in more detail in fedfs(7).
32 The second argument, localdir, specifies the local directory on which
34 to mount the requested FedFS globally useful name. As with other file
35 systems, localdir must exist on the client for a mount request to suc‐
36 ceed.
37 The mount.fedfs(8) command converts the specified remotedir and
39 localdir arguments, along with information obtained via DNS SRV
40 queries, to arguments suitable for a local mount request. It then
41 forks and execs the appropriate file system mount subcommand (such as
42 the mount.nfs(8) subcommand) to mount the file server where the domain
43 root resides.
44 Because an unmodified file system mount subcommand is used for the
46 actual mount operation, the file system's equivalent umount subcommand
47 is all that is required to unmount this mount point when it is finished
48 being used.
49 Mount option inheritance
51 The Linux NFS client treats an NFS referral as a server-initiated mount
52 request. The referring fileserver provides only a list of server names
53 and export paths. The mount options for this new mount are inherited
54 from the new mount point's parent directory on the client.
55 As applications proceed deeper into a domain's namespace, they can
57 encounter both file sets to which they have read-only access, and file
58 sets to which they have read-write access. To allow applications
59 proper access to both types of file sets, typically file-access clients
60 mount domain root directories in read-write mode. All submounts of the
61 domain root are then mounted read-write as well. Write access is then
62 controlled by fileservers.
63 For example, a domain root may contain an NFS version 4 referral to an
65 export containing user home directories. The domain root may be
66 exported read-only so file-access clients cannot update it, but user
67 home directories would not be very useful if they could not be written
68 to by their owners. The fileserver continues to employ user creden‐
69 tials to limit access as appropriate.
70 Network file system clients follow file system referrals as applica‐
72 tions encounter them, which is similar to how an automounter works.
73 Consider the initial mount of the domain root as if you are mounting a
74 single whole file system, even though underneath, additional NFS mounts
75 come and go as needed.
76 Options
78 -f, --fake
79 Fake mount. This option is ignored by mount.fedfs(8) but is
80 passed to the underlying file system mount subcommand.
81 -h, --help
83 Print the mount.fedfs(8) usage message and exit.
84 -n, --no-mtab
86 Do not update /etc/mtab. This option is ignored by
87 mount.fedfs(8) but is passed to the underlying file system mount
88 subcommand.
89 -o, --options options
91 Specify mount options for this mount point and all submounts.
92 These are ignored by mount.fedfs(8) but are passed to the under‐
93 lying file system mount subcommand. For further details, refer
94 to mount(8).
95 -r, --ro, --read-only
97 Mount the domain root and all submounts read-only.
98 -s, --sloppy
100 Tolerate unrecognized mount options. This is ignored by
101 mount.fedfs(8) but is passed to the underlying file system mount
102 subcommand.
103 -v, --verbose
105 Report more information during the mount process. This affects
106 mount.fedfs(8) and is also passed to the underlying file system
107 mount subcommand.
108 -V, --version
110 Print version information for mount.fedfs(8) and exit.
111 -w, --rw, --read-write
113 Mount the domain root and all submounts read-write. This is the
114 default behavior.
115
117 To mount the domain root of the example.net FedFS domain via NFS ver‐
118 sion 4 automatically, you might add this to your /etc/fstab:
119 /nfs4/example.net /nfs4/example.net fedfs defaults 0 0
121 A FedFS domain root can also be mounted with a stand-alone invocation
123 of mount(8):
124 # mount -t fedfs /nfs4/example.net /mnt/fedfs
126 This mounts the FedFS domain root for the example.net domain on the
128 client's /mnt/fedfs directory. A simple
129 # umount /mnt/fedfs
131 unmounts it when you are finished with it.
133
135 /etc/fstab filesystem table
136 /etc/mtab table of mounted file systems
138
140 fedfs(7), nfs(5), mount(8), mount.nfs(8)
141 RFC 2782 for a discussion of DNS SRV records
143 RFC 5661 for a description of NFS version 4 referrals
145 RFC 5716 for FedFS requirements and overview
147
149 This page is part of the fedfs-utils package. A description of the
150 project and information about reporting bugs can be found at
151 http://wiki.linux-nfs.org/wiki/index.php/FedFsUtilsProject.
152
154 Chuck Lever <chuck.lever@oracle.com>
155 3 February 2014 MOUNT.FEDFS(8)