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28 .\" @(#)fstab.5 8.1 (Berkeley) 6/5/93
36 .Nd static information about the file systems
42 contains descriptive information about the various file
45 is only read by programs, and not written;
46 it is the duty of the system administrator to properly create
47 and maintain this file.
48 Each file system is described on a separate line;
49 fields on each line are separated by tabs or spaces.
50 The order of records in
57 sequentially iterate through
63 describes the special device or
64 remote file system to be mounted.
65 The contents are decoded by the
68 This allows using spaces or tabs in the device name which would be
69 interpreted as field separators otherwise.
73 describes the mount point for the file system.
74 For swap partitions, this field should be specified as
76 The contents are decoded by the
82 describes the type of the file system.
83 The system can support various file system types.
84 Only the root, /usr, and /tmp file systems need be statically
85 compiled into the kernel;
86 everything else will be automatically loaded at mount
88 (Exception: the FFS cannot currently be demand-loaded.)
89 Some people still prefer to statically
90 compile other file systems as well.
94 describes the mount options associated with the file system.
95 It is formatted as a comma separated list of options.
96 It contains at least the type of mount (see
98 below) plus any additional options appropriate to the file system type.
103 page and the file system specific page, such as
105 for additional options that may be specified.
106 All options that can be given to the file system specific mount commands
110 They just need to be formatted a bit differently.
113 option can be used without the preceding
116 Other options need both the file system specific flag and its argument,
117 separated by an equal sign.
118 For example, mounting an
120 filesystem, the options
121 .Bd -literal -offset indent
122 -o sync -o noatime -m 644 -M 755 -u foo -g bar
126 .Bd -literal -offset indent
127 sync,noatime,-m=644,-M=755,-u=foo,-g=bar
130 in the option field of
138 the file system is automatically processed by the
140 command, and user and/or group disk quotas are enabled with
143 file system quotas are maintained in files named
147 which are located at the root of the associated file system.
148 These defaults may be overridden by putting an equal sign
149 and an alternative absolute pathname following the quota option.
150 Thus, if the user quota file for
153 .Pa /var/quotas/tmp.user ,
154 this location can be specified as:
155 .Bd -literal -offset indent
156 userquota=/var/quotas/tmp.user
162 the system will ignore any error which happens during the mount of that filesystem,
163 which would otherwise cause the system to drop into single user mode.
164 This option is implemented by the
166 command and will not be passed to the kernel.
170 is specified, the file system will not be automatically
171 mounted at system startup.
172 Note that, for network file systems
174 (i.e., types supported by additional software
175 not included in the base system)
176 to be automatically mounted at system startup,
178 .Va extra_netfs_types
180 variable must be used to extend the
182 startup script's list of network file system types.
186 is specified, the file system will be automatically mounted
187 at a stage of system startup after remote mount points are mounted.
188 For more detail about this option,
195 is specified, it indicates that the status of an already mounted file
196 system should be changed accordingly.
197 This allows, for example, file systems mounted read-only to be upgraded
198 read-write and vice-versa.
199 By default, an entry corresponding to a file systems that is already
200 mounted is going to be skipped over when processing
202 unless it's a root file system, in which case logic similar to
204 is applied automatically.
208 option is typically used in conjuction with two
213 file is used to set up the initial set of file systems.
216 file is then run to update the initial set of file systems and
217 to add additional file systems.
219 The type of the mount is extracted from the
221 field and stored separately in the
223 field (it is not deleted from the
232 then the file system whose name is given in the
234 field is normally mounted read-write or read-only on the
235 specified special file.
241 then the special file is made available as a piece of swap
244 command at the end of the system reboot procedure.
245 For swap devices, the keyword
247 triggers the delivery of a
249 command to the device.
250 This command marks the device's blocks as unused, except those that
251 might store a disk label.
252 This marking can erase a crash dump.
255 for a device until after
257 has copied the crash dump to another location, use the
260 For vnode-backed swap spaces,
270 .Pq Do md Dc or Do md[0-9]* Dc
277 device is created with the specified file used as backing store,
278 and then the new device is used as swap space.
281 devices will cause automatic creation of encrypted devices.
289 options may be passed to control those
292 The fields other than
301 the entry is ignored.
302 This is useful to show disk partitions which are currently unused.
306 is used for these file systems by the
308 command to determine which file systems need to be dumped.
309 If the fifth field is not present, a value of zero is returned and
311 will assume that the file system does not need to be dumped.
312 If the fifth field is greater than 0, then it specifies the number of days
313 between dumps for this file system.
321 programs to determine the order in which file system and quota
322 checks are done at reboot time.
325 field can be any value between 0 and
328 The root file system should be specified with a
330 of 1, and other file systems should have a
335 value of 1 is always checked sequentially and be completed before
336 another file system is processed, and it will be processed before
337 all file systems with a larger
340 For any given value of
342 file systems within a drive will be checked sequentially,
343 but file systems on different drives will be checked at the
344 same time to utilize parallelism available in the hardware.
345 Once all file system checks are complete for the current
347 the same process will start over for the next
350 If the sixth field is not present or is zero,
351 a value of zero is returned and
355 will assume that the file system does not need to be checked.
359 field can be used to implement finer control when
360 the system utilities may determine that the file system resides
361 on a different physical device, when it actually does not, as with a
364 All file systems with a lower
366 value will be completed before starting on file systems with a
370 E.g. all file systems with a
372 of 2 will be completed before any file systems with a
374 of 3 or greater are started.
375 Gaps are allowed between the different
378 E.g. file systems listed in
382 values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order
386 #define FSTAB_RW "rw" /* read/write device */
387 #define FSTAB_RQ "rq" /* read/write with quotas */
388 #define FSTAB_RO "ro" /* read-only device */
389 #define FSTAB_SW "sw" /* swap device */
390 #define FSTAB_XX "xx" /* ignore totally */
393 char *fs_spec; /* block special device name */
394 char *fs_file; /* file system path prefix */
395 char *fs_vfstype; /* File system type, ufs, nfs */
396 char *fs_mntops; /* Mount options ala -o */
397 char *fs_type; /* FSTAB_* from fs_mntops */
398 int fs_freq; /* dump frequency, in days */
399 int fs_passno; /* pass number on parallel fsck */
403 The proper way to read records from
405 is to use the routines
412 .Bl -tag -width /etc/fstab -compact
421 # Device Mountpoint FStype Options Dump Pass#
424 /dev/da0p2 / ufs rw 1 1
426 # Swap space on a block device.
427 /dev/da0p1 none swap sw 0 0
429 # Swap space using a block device with GBDE/GELI encyption.
430 # aalgo, ealgo, keylen, sectorsize options are available
432 /dev/da1p1.bde none swap sw 0 0
433 /dev/da1p2.eli none swap sw 0 0
436 tmpfs /tmp tmpfs rw,size=1g,mode=1777 0 0
438 # UFS file system on a swap-backed md(4). /dev/md10 is
439 # automatically created. If it is "md", a unit number
440 # will be automatically selected.
441 md10 /scratch mfs rw,-s1g 0 0
443 # Swap space on a vnode-backed md(4).
444 md11 none swap sw,file=/swapfile 0 0
446 # CDROM. "noauto" option is typically used because the
447 # media is removable.
448 /dev/cd0 /cdrom cd9660 ro,noauto 0 0
450 # NFS-exported file system. "serv" is an NFS server name
452 serv:/export /nfs nfs rw,noinet6 0 0
470 file format appeared in