1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 33.\" $FreeBSD$ 34.\" 35.Dd October 11, 2012 36.Dt FSTAB 5 37.Os 38.Sh NAME 39.Nm fstab 40.Nd static information about the file systems 41.Sh SYNOPSIS 42.In fstab.h 43.Sh DESCRIPTION 44The file 45.Nm 46contains descriptive information about the various file 47systems. 48.Nm 49is only read by programs, and not written; 50it is the duty of the system administrator to properly create 51and maintain this file. 52Each file system is described on a separate line; 53fields on each line are separated by tabs or spaces. 54The order of records in 55.Nm 56is important because 57.Xr fsck 8 , 58.Xr mount 8 , 59and 60.Xr umount 8 61sequentially iterate through 62.Nm 63doing their thing. 64.Pp 65The first field, 66.Pq Fa fs_spec , 67describes the special device or 68remote file system to be mounted. 69The contents are decoded by the 70.Xr strunvis 3 71function. 72This allows using spaces or tabs in the device name which would be 73interpreted as field separators otherwise. 74.Pp 75The second field, 76.Pq Fa fs_file , 77describes the mount point for the file system. 78For swap partitions, this field should be specified as 79.Dq none . 80The contents are decoded by the 81.Xr strunvis 3 82function, as above. 83.Pp 84The third field, 85.Pq Fa fs_vfstype , 86describes the type of the file system. 87The system can support various file system types. 88Only the root, /usr, and /tmp file systems need be statically 89compiled into the kernel; 90everything else will be automatically loaded at mount 91time. 92(Exception: the FFS cannot currently be demand-loaded.) 93Some people still prefer to statically 94compile other file systems as well. 95.Pp 96The fourth field, 97.Pq Fa fs_mntops , 98describes the mount options associated with the file system. 99It is formatted as a comma separated list of options. 100It contains at least the type of mount (see 101.Fa fs_type 102below) plus any additional options appropriate to the file system type. 103See the options flag 104.Pq Fl o 105in the 106.Xr mount 8 107page and the file system specific page, such as 108.Xr mount_nfs 8 , 109for additional options that may be specified. 110All options that can be given to the file system specific mount commands 111can be used in 112.Nm 113as well. 114They just need to be formatted a bit differently. 115The arguments of the 116.Fl o 117option can be used without the preceding 118.Fl o 119flag. 120Other options need both the file system specific flag and its argument, 121separated by an equal sign. 122For example, mounting an 123.Xr msdosfs 5 124filesystem, the options 125.Bd -literal -offset indent 126-o sync -o noatime -m 644 -M 755 -u foo -g bar 127.Ed 128.Pp 129should be written as 130.Bd -literal -offset indent 131sync,noatime,-m=644,-M=755,-u=foo,-g=bar 132.Ed 133.Pp 134in the option field of 135.Nm . 136.Pp 137If the options 138.Dq userquota 139and/or 140.Dq groupquota 141are specified, 142the file system is automatically processed by the 143.Xr quotacheck 8 144command, and user and/or group disk quotas are enabled with 145.Xr quotaon 8 . 146By default, 147file system quotas are maintained in files named 148.Pa quota.user 149and 150.Pa quota.group 151which are located at the root of the associated file system. 152These defaults may be overridden by putting an equal sign 153and an alternative absolute pathname following the quota option. 154Thus, if the user quota file for 155.Pa /tmp 156is stored in 157.Pa /var/quotas/tmp.user , 158this location can be specified as: 159.Bd -literal -offset indent 160userquota=/var/quotas/tmp.user 161.Ed 162.Pp 163If the option 164.Dq failok 165is specified, 166the system will ignore any error which happens during the mount of that filesystem, 167which would otherwise cause the system to drop into single user mode. 168This option is implemented by the 169.Xr mount 8 170command and will not be passed to the kernel. 171.Pp 172If the option 173.Dq noauto 174is specified, the file system will not be automatically 175mounted at system startup. 176Note that, for network file systems 177of third party types 178(i.e., types supported by additional software 179not included in the base system) 180to be automatically mounted at system startup, 181the 182.Va extra_netfs_types 183.Xr rc.conf 5 184variable must be used to extend the 185.Xr rc 8 186startup script's list of network file system types. 187.Pp 188The type of the mount is extracted from the 189.Fa fs_mntops 190field and stored separately in the 191.Fa fs_type 192field (it is not deleted from the 193.Fa fs_mntops 194field). 195If 196.Fa fs_type 197is 198.Dq rw 199or 200.Dq ro 201then the file system whose name is given in the 202.Fa fs_file 203field is normally mounted read-write or read-only on the 204specified special file. 205If 206.Fa fs_type 207is 208.Dq sw 209then the special file is made available as a piece of swap 210space by the 211.Xr swapon 8 212command at the end of the system reboot procedure. 213The fields other than 214.Fa fs_spec 215and 216.Fa fs_type 217are unused. 218If 219.Fa fs_type 220is specified as 221.Dq xx 222the entry is ignored. 223This is useful to show disk partitions which are currently unused. 224.Pp 225The fifth field, 226.Pq Fa fs_freq , 227is used for these file systems by the 228.Xr dump 8 229command to determine which file systems need to be dumped. 230If the fifth field is not present, a value of zero is returned and 231.Nm dump 232will assume that the file system does not need to be dumped. 233If the fifth field is greater than 0, then it specifies the number of days 234between dumps for this file system. 235.Pp 236The sixth field, 237.Pq Fa fs_passno , 238is used by the 239.Xr fsck 8 240and 241.Xr quotacheck 8 242programs to determine the order in which file system and quota 243checks are done at reboot time. 244The 245.Fa fs_passno 246field can be any value between 0 and 247.Ql INT_MAX Ns -1 . 248.Pp 249The root file system should be specified with a 250.Fa fs_passno 251of 1, and other file systems should have a 252.Fa fs_passno 253of 2 or greater. 254A file system with a 255.Fa fs_passno 256value of 1 is always checked sequentially and be completed before 257another file system is processed, and it will be processed before 258all file systems with a larger 259.Fa fs_passno . 260.Pp 261For any given value of 262.Fa fs_passno , 263file systems within a drive will be checked sequentially, 264but file systems on different drives will be checked at the 265same time to utilize parallelism available in the hardware. 266Once all file system checks are complete for the current 267.Fa fs_passno , 268the same process will start over for the next 269.Fa fs_passno . 270.Pp 271If the sixth field is not present or is zero, 272a value of zero is returned and 273.Xr fsck 8 274and 275.Xr quotacheck 8 276will assume that the file system does not need to be checked. 277.Pp 278The 279.Fa fs_passno 280field can be used to implement finer control when 281the system utilities may determine that the file system resides 282on a different physical device, when it actually does not, as with a 283.Xr ccd 4 284device. 285All file systems with a lower 286.Fa fs_passno 287value will be completed before starting on file systems with a 288higher 289.Fa fs_passno 290value. 291E.g. all file systems with a 292.Fa fs_passno 293of 2 will be completed before any file systems with a 294.Fa fs_passno 295of 3 or greater are started. 296Gaps are allowed between the different 297.Fa fs_passno 298values. 299E.g. file systems listed in 300.Pa /etc/fstab 301may have 302.Fa fs_passno 303values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order 304within 305.Pa /etc/fstab . 306.Bd -literal 307#define FSTAB_RW "rw" /* read/write device */ 308#define FSTAB_RQ "rq" /* read/write with quotas */ 309#define FSTAB_RO "ro" /* read-only device */ 310#define FSTAB_SW "sw" /* swap device */ 311#define FSTAB_XX "xx" /* ignore totally */ 312 313struct fstab { 314 char *fs_spec; /* block special device name */ 315 char *fs_file; /* file system path prefix */ 316 char *fs_vfstype; /* File system type, ufs, nfs */ 317 char *fs_mntops; /* Mount options ala -o */ 318 char *fs_type; /* FSTAB_* from fs_mntops */ 319 int fs_freq; /* dump frequency, in days */ 320 int fs_passno; /* pass number on parallel fsck */ 321}; 322.Ed 323.Pp 324The proper way to read records from 325.Pa fstab 326is to use the routines 327.Xr getfsent 3 , 328.Xr getfsspec 3 , 329.Xr getfstype 3 , 330and 331.Xr getfsfile 3 . 332.Sh FILES 333.Bl -tag -width /etc/fstab -compact 334.It Pa /etc/fstab 335The file 336.Nm 337resides in 338.Pa /etc . 339.El 340.Sh SEE ALSO 341.Xr getfsent 3 , 342.Xr getvfsbyname 3 , 343.Xr ccd 4 , 344.Xr dump 8 , 345.Xr fsck 8 , 346.Xr mount 8 , 347.Xr quotacheck 8 , 348.Xr quotaon 8 , 349.Xr strunvis 3 , 350.Xr swapon 8 , 351.Xr umount 8 352.Sh HISTORY 353The 354.Nm 355file format appeared in 356.Bx 4.0 . 357