1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
|
.\" Copyright (c) 1980, 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$
.\"
.Dd June 7, 2011
.Dt FSTAB 5
.Os
.Sh NAME
.Nm fstab
.Nd static information about the file systems
.Sh SYNOPSIS
.In fstab.h
.Sh DESCRIPTION
The file
.Nm
contains descriptive information about the various file
systems.
.Nm
is only read by programs, and not written;
it is the duty of the system administrator to properly create
and maintain this file.
Each file system is described on a separate line;
fields on each line are separated by tabs or spaces.
The order of records in
.Nm
is important because
.Xr fsck 8 ,
.Xr mount 8 ,
and
.Xr umount 8
sequentially iterate through
.Nm
doing their thing.
.Pp
The first field,
.Pq Fa fs_spec ,
describes the special device or
remote file system to be mounted.
.Pp
The second field,
.Pq Fa fs_file ,
describes the mount point for the file system.
For swap partitions, this field should be specified as ``none''.
.Pp
The third field,
.Pq Fa fs_vfstype ,
describes the type of the file system.
The system can support various file system types.
Only the root, /usr, and /tmp file systems need be statically
compiled into the kernel;
everything else will be automatically loaded at mount
time.
(Exception: the FFS cannot currently be demand-loaded.)
Some people still prefer to statically
compile other file systems as well.
.Pp
The fourth field,
.Pq Fa fs_mntops ,
describes the mount options associated with the file system.
It is formatted as a comma separated list of options.
It contains at least the type of mount (see
.Fa fs_type
below) plus any additional options appropriate to the file system type.
See the options flag
.Pq Fl o
in the
.Xr mount 8
page and the file system specific page, such as
.Xr mount_nfs 8 ,
for additional options that may be specified.
All options that can be given to the file system specific mount commands
can be used in
.Nm
as well.
They just need to be formatted a bit differently.
The arguments of the
.Fl o
option can be used without the preceding
.Fl o
flag.
Other options need both the file system specific flag and its argument,
separated by an equal sign.
For example, mounting an
.Xr msdosfs 5
filesystem, the options
.Bd -literal -offset indent
-o sync -o noatime -m 644 -M 755 -u foo -g bar
.Ed
.Pp
should be written as
.Bd -literal -offset indent
sync,noatime,-m=644,-M=755,-u=foo,-g=bar
.Ed
.Pp
in the option field of
.Nm .
.Pp
If the options ``userquota'' and/or ``groupquota'' are specified,
the file system is automatically processed by the
.Xr quotacheck 8
command, and user and/or group disk quotas are enabled with
.Xr quotaon 8 .
By default,
file system quotas are maintained in files named
.Pa quota.user
and
.Pa quota.group
which are located at the root of the associated file system.
These defaults may be overridden by putting an equal sign
and an alternative absolute pathname following the quota option.
Thus, if the user quota file for
.Pa /tmp
is stored in
.Pa /var/quotas/tmp.user ,
this location can be specified as:
.Bd -literal -offset indent
userquota=/var/quotas/tmp.user
.Ed
.Pp
If the option ``failok'' is specified,
the system will ignore any error which happens during the mount of that filesystem,
which would otherwise cause the system to drop into single user mode.
This option is implemented by the
.Xr mount 8
command and will not be passed to the kernel.
.Pp
If the option ``noauto'' is specified, the file system will not be automatically
mounted at system startup.
Note that, for network file systems
of third party types
(i.e., types supported by additional software
not included in the base system)
to be automatically mounted at system startup,
the
.Va extra_netfs_types
.Xr rc.conf 5
variable must be used to extend the
.Xr rc 8
startup script's list of network file system types.
.Pp
The type of the mount is extracted from the
.Fa fs_mntops
field and stored separately in the
.Fa fs_type
field (it is not deleted from the
.Fa fs_mntops
field).
If
.Fa fs_type
is ``rw'' or ``ro'' then the file system whose name is given in the
.Fa fs_file
field is normally mounted read-write or read-only on the
specified special file.
If
.Fa fs_type
is ``sw'' then the special file is made available as a piece of swap
space by the
.Xr swapon 8
command at the end of the system reboot procedure.
The fields other than
.Fa fs_spec
and
.Fa fs_type
are unused.
If
.Fa fs_type
is specified as ``xx'' the entry is ignored.
This is useful to show disk partitions which are currently unused.
.Pp
The fifth field,
.Pq Fa fs_freq ,
is used for these file systems by the
.Xr dump 8
command to determine which file systems need to be dumped.
If the fifth field is not present, a value of zero is returned and
.Nm dump
will assume that the file system does not need to be dumped.
If the fifth field is greater than 0, then it specifies the number of days
between dumps for this file system.
.Pp
The sixth field,
.Pq Fa fs_passno ,
is used by the
.Xr fsck 8
and
.Xr quotacheck 8
programs to determine the order in which file system and quota
checks are done at reboot time.
The
.Fa fs_passno
field can be any value between 0 and
.Ql INT_MAX Ns -1 .
.Pp
The root file system should be specified with a
.Fa fs_passno
of 1, and other file systems should have a
.Fa fs_passno
of 2 or greater.
A file system with a
.Fa fs_passno
value of 1 is always checked sequentially and be completed before
another file system is processed, and it will be processed before
all file systems with a larger
.Fa fs_passno .
.Pp
For any given value of
.Fa fs_passno ,
file systems within a drive will be checked sequentially,
but file systems on different drives will be checked at the
same time to utilize parallelism available in the hardware.
Once all file system checks are complete for the current
.Fa fs_passno ,
the same process will start over for the next
.Fa fs_passno .
.Pp
If the sixth field is not present or is zero,
a value of zero is returned and
.Xr fsck 8
and
.Xr quotacheck 8
will assume that the file system does not need to be checked.
.Pp
The
.Fa fs_passno
field can be used to implement finer control when
the system utilities may determine that the file system resides
on a different physical device, when it actually does not, as with a
.Xr ccd 4
device.
All file systems with a lower
.Fa fs_passno
value will be completed before starting on file systems with a
higher
.Fa fs_passno
value.
E.g. all file systems with a
.Fa fs_passno
of 2 will be completed before any file systems with a
.Fa fs_passno
of 3 or greater are started.
Gaps are allowed between the different
.Fa fs_passno
values.
E.g. file systems listed in
.Pa /etc/fstab
may have
.Fa fs_passno
values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order
within
.Pa /etc/fstab .
.Bd -literal
#define FSTAB_RW "rw" /* read/write device */
#define FSTAB_RQ "rq" /* read/write with quotas */
#define FSTAB_RO "ro" /* read-only device */
#define FSTAB_SW "sw" /* swap device */
#define FSTAB_XX "xx" /* ignore totally */
struct fstab {
char *fs_spec; /* block special device name */
char *fs_file; /* file system path prefix */
char *fs_vfstype; /* File system type, ufs, nfs */
char *fs_mntops; /* Mount options ala -o */
char *fs_type; /* FSTAB_* from fs_mntops */
int fs_freq; /* dump frequency, in days */
int fs_passno; /* pass number on parallel fsck */
};
.Ed
.Pp
The proper way to read records from
.Pa fstab
is to use the routines
.Xr getfsent 3 ,
.Xr getfsspec 3 ,
.Xr getfstype 3 ,
and
.Xr getfsfile 3 .
.Sh FILES
.Bl -tag -width /etc/fstab -compact
.It Pa /etc/fstab
The file
.Nm
resides in
.Pa /etc .
.El
.Sh SEE ALSO
.Xr getfsent 3 ,
.Xr getvfsbyname 3 ,
.Xr ccd 4 ,
.Xr dump 8 ,
.Xr fsck 8 ,
.Xr mount 8 ,
.Xr quotacheck 8 ,
.Xr quotaon 8 ,
.Xr swapon 8 ,
.Xr umount 8
.Sh HISTORY
The
.Nm
file format appeared in
.Bx 4.0 .
|