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1 | .\" Copyright (c) 1992 The Regents of the University of California. |
2 | .\" All rights reserved. | |
3 | .\" | |
4 | .\" %sccs.include.redist.roff% | |
5 | .\" | |
5bcf7ad5 | 6 | .\" @(#)mount_nfs.8 5.2 (Berkeley) %G% |
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7 | .\" |
8 | .Dd | |
9 | .Dt MOUNT_NFS 8 | |
10 | .Os BSD 4.4 | |
11 | .Sh NAME | |
12 | .Nm mount_nfs | |
13 | .Nd mount nfs file systems | |
14 | .Sh SYNOPSIS | |
15 | .Nm mount_nfs | |
5bcf7ad5 | 16 | .Op Fl bsiTMlqdckPK |
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17 | .Op Fl R Ar retrycnt |
18 | .Op Fl r Ar readsize | |
19 | .Op Fl w Ar writesize | |
20 | .Op Fl t Ar timeout | |
21 | .Op Fl x Ar retrans | |
22 | .Op Fl g Ar maxgroups | |
23 | .Op Fl a Ar maxreadahead | |
24 | .Op Fl L Ar leaseterm | |
25 | .Op Fl D Ar deadthresh | |
26 | .Op Fl m Ar realm | |
27 | .Ar rhost:path node | |
28 | .Sh DESCRIPTION | |
29 | The | |
30 | .Nm mount_nfs | |
31 | command | |
32 | calls the | |
33 | .Xr mount 2 | |
34 | system call to prepare and graft a | |
35 | remote nfs file system | |
36 | (rhost:path) | |
37 | on to the file system tree at the point | |
38 | .Ar node. | |
39 | This command is normally executed by | |
40 | .Xr mount 8 | |
41 | setting the options with the | |
42 | .Fl o | |
43 | flag. | |
44 | It implements the mount protocol as described in RFC 1094, Appendix A. | |
45 | .Pp | |
46 | The options are: | |
47 | .Bl -tag -width indent | |
48 | .It Fl b | |
49 | If an initial attempt to contact the server fails, fork off a child to keep | |
50 | trying the mount in the background. Useful for | |
51 | .Xr fstab 5 | |
52 | where the filesystem mount is not critical to multiuser operation. | |
53 | .It Fl s | |
54 | A soft mount, which implies that file system calls will fail | |
55 | after \fBRetry\fR round trip timeout intervals. | |
56 | .It Fl i | |
57 | An interruptible mount, which implies that file system calls that are delayed | |
58 | due to an unresponsive server will fail with EINTR when a termination signal | |
59 | is posted for the process. | |
60 | .It Fl T | |
61 | Use TCP transport instead of UDP. | |
62 | This is recommended for servers that are not on the | |
63 | same LAN cable as the client. | |
64 | (NB: This is NOT supported by most non-BSD servers.) | |
65 | .It Fl M | |
66 | Assume that other clients are not writing a file concurrently with this client. | |
67 | This implements a slightly less strict | |
68 | consistency criteria than 4.3BSD Reno did, | |
69 | that is more in line with most commercial client implementations. | |
70 | This is recommended for servers that do not support leasing. | |
71 | .It Fl d | |
72 | Do not estimate retransmit timeout dynamically. | |
73 | This may be useful for UDP | |
74 | mounts that exhibit high retry rates. | |
75 | .It Fl c | |
76 | For UDP mount points, do not do a | |
77 | .Xr connect 2. | |
78 | This must be used for servers that do not reply to requests from the standard | |
79 | port number. | |
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80 | .It Fl P |
81 | Use a reserved socket port number. This is useful for mounting servers that | |
82 | require clients to use a reserved port number. | |
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83 | .It Fl K |
84 | Pass Kerberos authenticators to the server for | |
85 | client-to-server user-credential mapping. | |
86 | This may only be used over TCP mounts between 4.4BSD clients and | |
87 | servers. | |
88 | .It Fl q | |
89 | Use the leasing extensions to the protocol to maintain cache consistency. | |
90 | This protocol, referred to as Not Quite Nfs (NQNFS), | |
91 | is only supported by 4.4BSD servers. | |
92 | .It Fl l | |
93 | Used with NQNFS to specify that the | |
94 | \fBReaddir_and_Lookup\fR RPC should be used. | |
95 | This option reduces RPC traffic for cases such as ``ls -l'', | |
96 | but increases the lease load on the server. | |
97 | This is recommended unless the server is complaining | |
98 | about excessive lease load. | |
99 | .It Fl k | |
100 | Used with NQNFS to specify ``get a lease'' for the file name being looked up. | |
101 | This is recommended unless the server is complaining about excessive lease | |
102 | load. | |
103 | .El | |
104 | .Pp | |
105 | The following arguments take a value parameter that is either a decimal | |
106 | number or a character string specified as =<value> after the option flag. | |
107 | .Bl -tag -width indent | |
108 | .It Fl R | |
109 | Set the retry count for doing the mount to <value>. | |
110 | .It Fl x | |
111 | Set the retransmit timeout count for soft mounts to <value>. | |
112 | .It Fl r | |
113 | Set the read data size to <value>. | |
114 | It should be a power of 2 greater than 512. | |
115 | This should be used for UDP mounts when the | |
116 | ``fragments dropped due to timeout'' | |
117 | value is getting large while actively using a mount point. | |
118 | (Use | |
119 | .Xr netstat 1 | |
120 | with the | |
121 | .FL s | |
122 | option to see what the ``fragments dropped due to timeout'' value is.) | |
123 | .It Fl w | |
124 | Set the write data size to <value>. | |
125 | Ditto the comments w.r.t. the | |
126 | .Fl r | |
127 | option, but using the ``fragments dropped due to timeout'' value on the | |
128 | server instead of the client. | |
129 | Note that both the | |
130 | .Fl r | |
131 | and | |
132 | .Fl w | |
133 | options should only be used as a last ditch effort at improving performance | |
134 | when mounting servers that do not support TCP mounts. | |
135 | .It Fl t | |
136 | Set the initial retransmit timeout to <value>. | |
137 | May be useful for fine tuning UDP mounts over internetworks | |
138 | with high packet loss rates or an overloaded server. | |
139 | Try increasing the interval if | |
140 | .Xr nfsstat 1 | |
141 | shows high retransmit rates while the file system is active or reducing the | |
142 | value if there is a low retransmit rate but long response delay observed. | |
143 | .It Fl g | |
144 | Set the maximum size of the group list for the credentials to <value>. | |
145 | This should be used for mounts on old servers that cannot handle a group list | |
146 | size of 16, as specified in RFC 1057. | |
147 | Try 8, if users in a lot of groups | |
148 | cannot get response from the mount point. | |
149 | .It Fl a | |
150 | Set the read-ahead count to <value>. | |
151 | This may be in the range of 0 - 4 and determines how many blocks | |
152 | will be read ahead when a large file is being read sequentially. | |
153 | This is recommended for mounts with a large | |
154 | bandwidth * delay product. | |
155 | .It Fl L | |
156 | Used with NQNFS to set the lease term to <value> seconds. | |
157 | Only use this argument for mounts with a large round trip delay. | |
158 | Values are normally in the 10-30 second range. | |
159 | .It Fl D | |
160 | Used with NQNFS to set the ``dead server threshold'' to <value> round trip | |
161 | timeout intervals. | |
162 | After a ``dead server threshold'' of retransmit timeouts, | |
163 | cached data for the unresponsive server is assumed to still be valid. | |
164 | Values may be set in the range of 1 - 9, with 9 referring to an ``infinite | |
165 | dead threshold'' (i.e. never assume cached data still valid). | |
166 | This option is not generally recommended and | |
167 | is really an experimental feature. | |
168 | .It Fl m | |
169 | Set the Kerberos realm to the string argument. Used with the | |
170 | .Fl K | |
171 | option for mounts to other realms. | |
172 | .El | |
173 | .Sh SEE ALSO | |
174 | .Xr mount 2 , | |
175 | .Xr unmount 2 , | |
176 | .Xr fstab 5 | |
177 | .Sh BUGS | |
178 | Due to the way that Sun RPC is implemented on top of UDP (unreliable datagram) | |
179 | transport, tuning such mounts is really a black art that can only be expected | |
180 | to have limited success. | |
181 | For clients mounting servers that are not on the same | |
182 | LAN cable or that tend to be overloaded, | |
183 | TCP transport is strongly recommended, | |
184 | but unfortunately this is restricted to mostly 4.4BSD servers. |