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 June 7, 2011 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. 69.Pp 70The second field, 71.Pq Fa fs_file , 72describes the mount point for the file system. 73For swap partitions, this field should be specified as 74.Dq none . 75.Pp 76The third field, 77.Pq Fa fs_vfstype , 78describes the type of the file system. 79The system can support various file system types. 80Only the root, /usr, and /tmp file systems need be statically 81compiled into the kernel; 82everything else will be automatically loaded at mount 83time. 84(Exception: the FFS cannot currently be demand-loaded.) 85Some people still prefer to statically 86compile other file systems as well. 87.Pp 88The fourth field, 89.Pq Fa fs_mntops , 90describes the mount options associated with the file system. 91It is formatted as a comma separated list of options. 92It contains at least the type of mount (see 93.Fa fs_type 94below) plus any additional options appropriate to the file system type. 95See the options flag 96.Pq Fl o 97in the 98.Xr mount 8 99page and the file system specific page, such as 100.Xr mount_nfs 8 , 101for additional options that may be specified. 102All options that can be given to the file system specific mount commands 103can be used in 104.Nm 105as well. 106They just need to be formatted a bit differently. 107The arguments of the 108.Fl o 109option can be used without the preceding 110.Fl o 111flag. 112Other options need both the file system specific flag and its argument, 113separated by an equal sign. 114For example, mounting an 115.Xr msdosfs 5 116filesystem, the options 117.Bd -literal -offset indent 118-o sync -o noatime -m 644 -M 755 -u foo -g bar 119.Ed 120.Pp 121should be written as 122.Bd -literal -offset indent 123sync,noatime,-m=644,-M=755,-u=foo,-g=bar 124.Ed 125.Pp 126in the option field of 127.Nm . 128.Pp 129If the options 130.Dq userquota 131and/or 132.Dq groupquota 133are specified, 134the file system is automatically processed by the 135.Xr quotacheck 8 136command, and user and/or group disk quotas are enabled with 137.Xr quotaon 8 . 138By default, 139file system quotas are maintained in files named 140.Pa quota.user 141and 142.Pa quota.group 143which are located at the root of the associated file system. 144These defaults may be overridden by putting an equal sign 145and an alternative absolute pathname following the quota option. 146Thus, if the user quota file for 147.Pa /tmp 148is stored in 149.Pa /var/quotas/tmp.user , 150this location can be specified as: 151.Bd -literal -offset indent 152userquota=/var/quotas/tmp.user 153.Ed 154.Pp 155If the option 156.Dq failok 157is specified, 158the system will ignore any error which happens during the mount of that filesystem, 159which would otherwise cause the system to drop into single user mode. 160This option is implemented by the 161.Xr mount 8 162command and will not be passed to the kernel. 163.Pp 164If the option 165.Dq noauto 166is specified, the file system will not be automatically 167mounted at system startup. 168Note that, for network file systems 169of third party types 170(i.e., types supported by additional software 171not included in the base system) 172to be automatically mounted at system startup, 173the 174.Va extra_netfs_types 175.Xr rc.conf 5 176variable must be used to extend the 177.Xr rc 8 178startup script's list of network file system types. 179.Pp 180The type of the mount is extracted from the 181.Fa fs_mntops 182field and stored separately in the 183.Fa fs_type 184field (it is not deleted from the 185.Fa fs_mntops 186field). 187If 188.Fa fs_type 189is 190.Dq rw 191or 192.Dq ro 193then the file system whose name is given in the 194.Fa fs_file 195field is normally mounted read-write or read-only on the 196specified special file. 197If 198.Fa fs_type 199is 200.Dq sw 201then the special file is made available as a piece of swap 202space by the 203.Xr swapon 8 204command at the end of the system reboot procedure. 205The fields other than 206.Fa fs_spec 207and 208.Fa fs_type 209are unused. 210If 211.Fa fs_type 212is specified as 213.Dq xx 214the entry is ignored. 215This is useful to show disk partitions which are currently unused. 216.Pp 217The fifth field, 218.Pq Fa fs_freq , 219is used for these file systems by the 220.Xr dump 8 221command to determine which file systems need to be dumped. 222If the fifth field is not present, a value of zero is returned and 223.Nm dump 224will assume that the file system does not need to be dumped. 225If the fifth field is greater than 0, then it specifies the number of days 226between dumps for this file system. 227.Pp 228The sixth field, 229.Pq Fa fs_passno , 230is used by the 231.Xr fsck 8 232and 233.Xr quotacheck 8 234programs to determine the order in which file system and quota 235checks are done at reboot time. 236The 237.Fa fs_passno 238field can be any value between 0 and 239.Ql INT_MAX Ns -1 . 240.Pp 241The root file system should be specified with a 242.Fa fs_passno 243of 1, and other file systems should have a 244.Fa fs_passno 245of 2 or greater. 246A file system with a 247.Fa fs_passno 248value of 1 is always checked sequentially and be completed before 249another file system is processed, and it will be processed before 250all file systems with a larger 251.Fa fs_passno . 252.Pp 253For any given value of 254.Fa fs_passno , 255file systems within a drive will be checked sequentially, 256but file systems on different drives will be checked at the 257same time to utilize parallelism available in the hardware. 258Once all file system checks are complete for the current 259.Fa fs_passno , 260the same process will start over for the next 261.Fa fs_passno . 262.Pp 263If the sixth field is not present or is zero, 264a value of zero is returned and 265.Xr fsck 8 266and 267.Xr quotacheck 8 268will assume that the file system does not need to be checked. 269.Pp 270The 271.Fa fs_passno 272field can be used to implement finer control when 273the system utilities may determine that the file system resides 274on a different physical device, when it actually does not, as with a 275.Xr ccd 4 276device. 277All file systems with a lower 278.Fa fs_passno 279value will be completed before starting on file systems with a 280higher 281.Fa fs_passno 282value. 283E.g. all file systems with a 284.Fa fs_passno 285of 2 will be completed before any file systems with a 286.Fa fs_passno 287of 3 or greater are started. 288Gaps are allowed between the different 289.Fa fs_passno 290values. 291E.g. file systems listed in 292.Pa /etc/fstab 293may have 294.Fa fs_passno 295values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order 296within 297.Pa /etc/fstab . 298.Bd -literal 299#define FSTAB_RW "rw" /* read/write device */ 300#define FSTAB_RQ "rq" /* read/write with quotas */ 301#define FSTAB_RO "ro" /* read-only device */ 302#define FSTAB_SW "sw" /* swap device */ 303#define FSTAB_XX "xx" /* ignore totally */ 304 305struct fstab { 306 char *fs_spec; /* block special device name */ 307 char *fs_file; /* file system path prefix */ 308 char *fs_vfstype; /* File system type, ufs, nfs */ 309 char *fs_mntops; /* Mount options ala -o */ 310 char *fs_type; /* FSTAB_* from fs_mntops */ 311 int fs_freq; /* dump frequency, in days */ 312 int fs_passno; /* pass number on parallel fsck */ 313}; 314.Ed 315.Pp 316The proper way to read records from 317.Pa fstab 318is to use the routines 319.Xr getfsent 3 , 320.Xr getfsspec 3 , 321.Xr getfstype 3 , 322and 323.Xr getfsfile 3 . 324.Sh FILES 325.Bl -tag -width /etc/fstab -compact 326.It Pa /etc/fstab 327The file 328.Nm 329resides in 330.Pa /etc . 331.El 332.Sh SEE ALSO 333.Xr getfsent 3 , 334.Xr getvfsbyname 3 , 335.Xr ccd 4 , 336.Xr dump 8 , 337.Xr fsck 8 , 338.Xr mount 8 , 339.Xr quotacheck 8 , 340.Xr quotaon 8 , 341.Xr swapon 8 , 342.Xr umount 8 343.Sh HISTORY 344The 345.Nm 346file format appeared in 347.Bx 4.0 . 348