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32 .\" @(#)fstab.5 8.1 (Berkeley) 6/5/93
40 .Nd static information about the file systems
46 contains descriptive information about the various file
49 is only read by programs, and not written;
50 it is the duty of the system administrator to properly create
51 and maintain this file.
52 Each file system is described on a separate line;
53 fields on each line are separated by tabs or spaces.
54 The order of records in
61 sequentially iterate through
67 describes the special device or
68 remote file system to be mounted.
72 describes the mount point for the file system.
73 For swap partitions, this field should be specified as ``none''.
77 describes the type of the file system.
78 The system can support various file system types.
79 Only the root, /usr, and /tmp file systems need be statically
80 compiled into the kernel;
81 everything else will be automatically loaded at mount
83 (Exception: the FFS cannot currently be demand-loaded.)
84 Some people still prefer to statically
85 compile other file systems as well.
89 describes the mount options associated with the file system.
90 It is formatted as a comma separated list of options.
91 It contains at least the type of mount (see
93 below) plus any additional options appropriate to the file system type.
98 page and the file system specific page, such as
100 for additional options that may be specified.
101 All options that can be given to the file system specific mount commands
105 They just need to be formatted a bit differently.
108 option can be used without the preceding
111 Other options need both the file system specific flag and its argument,
112 separated by an equal sign.
113 For example, mounting an
115 filesystem, the options
116 .Bd -literal -offset indent
117 -o sync -o noatime -m 644 -M 755 -u foo -g bar
121 .Bd -literal -offset indent
122 sync,noatime,-m=644,-M=755,-u=foo,-g=bar
125 in the option field of
128 If the options ``userquota'' and/or ``groupquota'' are specified,
129 the file system is automatically processed by the
131 command, and user and/or group disk quotas are enabled with
134 file system quotas are maintained in files named
138 which are located at the root of the associated file system.
139 These defaults may be overridden by putting an equal sign
140 and an alternative absolute pathname following the quota option.
141 Thus, if the user quota file for
144 .Pa /var/quotas/tmp.user ,
145 this location can be specified as:
146 .Bd -literal -offset indent
147 userquota=/var/quotas/tmp.user
150 If the option ``failok'' is specified,
151 the system will ignore any error which happens during the mount of that filesystem,
152 which would otherwise cause the system to drop into single user mode.
153 This option is implemented by the
155 command and will not be passed to the kernel.
157 If the option ``noauto'' is specified, the file system will not be automatically
158 mounted at system startup.
159 Note that, for network file systems
161 (i.e., types supported by additional software
162 not included in the base system)
163 to be automatically mounted at system startup,
165 .Va extra_netfs_types
167 variable must be used to extend the
169 startup script's list of network file system types.
171 The type of the mount is extracted from the
173 field and stored separately in the
175 field (it is not deleted from the
180 is ``rw'' or ``ro'' then the file system whose name is given in the
182 field is normally mounted read-write or read-only on the
183 specified special file.
186 is ``sw'' then the special file is made available as a piece of swap
189 command at the end of the system reboot procedure.
190 The fields other than
197 is specified as ``xx'' the entry is ignored.
198 This is useful to show disk partitions which are currently unused.
202 is used for these file systems by the
204 command to determine which file systems need to be dumped.
205 If the fifth field is not present, a value of zero is returned and
207 will assume that the file system does not need to be dumped.
208 If the fifth field is greater than 0, then it specifies the number of days
209 between dumps for this file system.
217 programs to determine the order in which file system and quota
218 checks are done at reboot time.
221 field can be any value between 0 and
224 The root file system should be specified with a
226 of 1, and other file systems should have a
231 value of 1 is always checked sequentially and be completed before
232 another file system is processed, and it will be processed before
233 all file systems with a larger
236 For any given value of
238 file systems within a drive will be checked sequentially,
239 but file systems on different drives will be checked at the
240 same time to utilize parallelism available in the hardware.
241 Once all file system checks are complete for the current
243 the same process will start over for the next
246 If the sixth field is not present or is zero,
247 a value of zero is returned and
251 will assume that the file system does not need to be checked.
255 field can be used to implement finer control when
256 the system utilities may determine that the file system resides
257 on a different physical device, when it actually does not, as with a
260 All file systems with a lower
262 value will be completed before starting on file systems with a
266 E.g. all file systems with a
268 of 2 will be completed before any file systems with a
270 of 3 or greater are started.
271 Gaps are allowed between the different
274 E.g. file systems listed in
278 values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order
282 #define FSTAB_RW "rw" /* read/write device */
283 #define FSTAB_RQ "rq" /* read/write with quotas */
284 #define FSTAB_RO "ro" /* read-only device */
285 #define FSTAB_SW "sw" /* swap device */
286 #define FSTAB_XX "xx" /* ignore totally */
289 char *fs_spec; /* block special device name */
290 char *fs_file; /* file system path prefix */
291 char *fs_vfstype; /* File system type, ufs, nfs */
292 char *fs_mntops; /* Mount options ala -o */
293 char *fs_type; /* FSTAB_* from fs_mntops */
294 int fs_freq; /* dump frequency, in days */
295 int fs_passno; /* pass number on parallel fsck */
299 The proper way to read records from
301 is to use the routines
308 .Bl -tag -width /etc/fstab -compact
329 file format appeared in