1.\" $OpenBSD: fstab.5,v 1.27 2003/06/06 13:28:13 jmc Exp $ 2.\" $NetBSD: fstab.5,v 1.5.2.1 1995/11/16 20:11:11 pk Exp $ 3.\" 4.\" Copyright (c) 1980, 1989, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 32.\" 33.Dd June 5, 1993 34.Dt FSTAB 5 35.Os 36.Sh NAME 37.Nm fstab 38.Nd static information about the filesystems 39.Sh SYNOPSIS 40.Fd #include <fstab.h> 41.Sh DESCRIPTION 42The 43.Nm 44file contains descriptive information about the various file systems. 45.Nm 46is only read by programs, and not written; 47it is the duty of the system administrator to properly create 48and maintain this file. 49Each filesystem is described on a separate line; 50fields on each line are separated by tabs or spaces. 51The order of records in 52.Nm 53is important because 54.Xr fsck 8 , 55.Xr mount 8 , 56and 57.Xr umount 8 58sequentially iterate through 59.Nm 60doing their thing. 61.Pp 62The first field, 63.Fa fs_spec , 64describes the block special device or remote filesystem to be mounted. 65For filesystems of type 66.Tn ffs , 67the special file name is the block special file name, 68and not the character special file name. 69If a program needs the character special file name, 70the program must create it by appending an 71.Dq r 72after the last 73.Dq / 74in the special file name. 75.Pp 76The second field, 77.Fa fs_file , 78describes the mount point for the filesystem. 79For swap partitions, this field should be specified as 80.Dq none . 81.Pp 82The third field, 83.Fa fs_vfstype , 84describes the type of the filesystem. 85The system currently supports twelve types of filesystems: 86.Pp 87.Bl -tag -width indent -offset indent -compact 88.It adosfs 89An 90.Tn AmigaDOS 91filesystem. 92.It cd9660 93An ISO9660 CD-ROM filesystem. 94.It fdesc 95An implementation of 96.Pa /dev/fd . 97.It ffs 98A local 99.Ux 100filesystem. 101.It ext2fs 102A local Linux compatible ext2fs 103filesystem. 104.It kernfs 105Various and sundry kernel statistics. 106.It mfs 107A local memory-based 108.Ux 109filesystem. 110.It msdos 111An 112.Tn MS-DOS 113FAT filesystem. 114.It nfs 115A Sun Microsystems compatible Network File System. 116.It procfs 117A local filesystem containing process information. 118.It swap 119A disk partition to be used for swapping. 120.It union 121A translucent filesystem. 122.El 123.Pp 124The fourth field, 125.Fa fs_mntops , 126describes the mount options associated with the filesystem. 127It is formatted as a comma separated list of options. 128It contains at least the type of mount (see 129.Fa fs_type 130below) plus any additional options appropriate to the filesystem type. 131.Pp 132The option 133.Dq auto 134can be used in the 135.Dq noauto 136form to cause 137a file system not to be mounted automatically (with 138.Ic mount -a , 139or at system boot time). 140.Pp 141If the options 142.Dq userquota 143and/or 144.Dq groupquota 145are specified, the filesystem is automatically processed by the 146.Xr quotacheck 8 147command, and user and/or group disk quotas are enabled with 148.Xr quotaon 8 . 149By default, filesystem quotas are maintained in files named 150.Pa quota.user 151and 152.Pa quota.group 153which are located at the root of the associated filesystem. 154These defaults may be overridden by putting an equal sign 155and an alternative absolute pathname following the quota option. 156Thus, if the user quota file for 157.Pa /tmp 158is stored in 159.Pa /var/quotas/tmp.user , 160this location can be specified as: 161.Bd -literal -offset indent 162userquota=/var/quotas/tmp.user 163.Ed 164.Pp 165The type of the mount is extracted from the first parameter of the 166.Fa fs_mntops 167field and stored separately in the 168.Fa fs_type 169field (it is not deleted from the 170.Fa fs_mntops 171field). 172If 173.Fa fs_type 174is 175.Dq rw 176or 177.Dq ro 178then the filesystem whose name is given in the 179.Fa fs_file 180field is normally mounted read-write or read-only on the 181specified special file. 182If 183.Fa fs_type 184is 185.Dq sw 186then the special file is made available as a piece of swap space by the 187.Xr swapon 8 188command at the end of the system reboot procedure. 189The fields other than 190.Fa fs_spec 191and 192.Fa fs_type 193are unused. 194If 195.Fa fs_type 196is specified as 197.Dq xx 198the entry is ignored. 199This is useful to show disk partitions which are currently unused. 200.Pp 201The fifth field, 202.Fa fs_freq , 203is used for these filesystems by the 204.Xr dump 8 205command to determine which filesystems need to be dumped. 206If the fifth field is not present, a value of zero is returned and 207.Xr dump 8 208will assume that the filesystem does not need to be dumped. 209.Pp 210The sixth field, 211.Fa fs_passno , 212is used by the 213.Xr fsck 8 214program to determine the order in which filesystem checks are done 215at reboot time. 216The root filesystem should be specified with a 217.Fa fs_passno 218of 1, and other filesystems should have a 219.Fa fs_passno 220of 2. 221Filesystems within a drive will be checked sequentially, 222but filesystems on different drives will be checked at the 223same time to utilize parallelism available in the hardware. 224If the sixth field is not present or is zero, 225a value of zero is returned and 226.Xr fsck 8 227will assume that the filesystem does not need to be checked. 228.Bd -literal 229#define FSTAB_RW "rw" /* read-write device */ 230#define FSTAB_RO "ro" /* read-only device */ 231#define FSTAB_SW "sw" /* swap device */ 232#define FSTAB_XX "xx" /* ignore totally */ 233 234struct fstab { 235 char *fs_spec; /* block special device name */ 236 char *fs_file; /* filesystem path prefix */ 237 char *fs_vfstype; /* type of filesystem */ 238 char *fs_mntops; /* comma separated mount options */ 239 char *fs_type; /* rw, ro, sw, or xx */ 240 int fs_freq; /* dump frequency, in days */ 241 int fs_passno; /* pass number on parallel fsck */ 242}; 243.Ed 244.Pp 245The proper way to read records from 246.Pa fstab 247is to use the routines 248.Xr getfsent 3 , 249.Xr getfsspec 3 , 250.Xr getfstype 3 , 251and 252.Xr getfsfile 3 . 253.Sh FILES 254.Bl -tag -width /etc/fstab -compact 255.It Pa /etc/fstab 256.El 257.Sh EXAMPLES 258Here is a sample 259.Pa /etc/fstab 260file: 261.Bd -literal -offset indent 262/dev/sd0a / ffs rw 1 1 263/dev/sd0e /var ffs rw,nodev,nosuid 1 2 264#/dev/sd0f /tmp ffs rw,nodev,nosuid 1 2 265/dev/sd0b /tmp mfs rw,nodev,nosuid,-s=153600 0 0 266/dev/sd0g /usr ffs rw,nodev 1 2 267/dev/sd0h /usr/local ffs rw,nodev 1 2 268/dev/sd0i /home ffs rw,nodev,nosuid 1 2 269/dev/sd1b none swap sw 0 0 270/dev/cd0a /cdrom cd9660 ro,noauto 0 0 271/kern /kern kernfs ro 0 0 272/proc /proc procfs rw 0 0 273server:/export/ports /usr/ports nfs rw,nodev,nosuid,tcp,soft,intr 0 0 274.Ed 275.Sh SEE ALSO 276.Xr quota 1 , 277.Xr getfsent 3 , 278.Xr fsck 8 , 279.Xr mount 8 , 280.Xr quotacheck 8 , 281.Xr quotaon 8 , 282.Xr umount 8 283.Sh HISTORY 284The 285.Nm 286file format appeared in 287.Bx 4.0 . 288