1.\" $NetBSD: fstab.5,v 1.21 2000/11/09 00:06:17 lukem Exp $ 2.\" 3.\" Copyright (c) 1980, 1989, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 35.\" 36.Dd November 9, 2000 37.Dt FSTAB 5 38.Os 39.Sh NAME 40.Nm fstab 41.Nd filesystem table for devices, types, and mount points 42.Sh SYNOPSIS 43.Fd #include <fstab.h> 44.Sh DESCRIPTION 45The file 46.Nm 47contains descriptive information about the various file systems. 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 filesystem is described on a separate line; 53fields on each line are separated by tabs or spaces. Lines beginning 54with 55.Dq # 56are comments. 57The order of records in 58.Nm 59is important because 60.Xr fsck 8 , 61.Xr mount 8 , 62and 63.Xr umount 8 64sequentially iterate through 65.Nm 66doing their respective tasks. 67.Pp 68Each configuration line/record in 69.Nm 70has the format: 71.Dl fs_spec fs_file fs_vfstype fs_mntops fs_freq fs_passno 72.Pp 73The first field, 74.Pq Fa fs_spec , 75describes the block special device or 76remote filesystem to be mounted. 77For filesystems of type 78.Em ffs , 79the special file name is the block special file name, 80and not the character special file name. 81If a program needs the character special file name, 82the program must create it by appending a 83.Dq r 84after the 85last 86.Dq / 87in the special file name. 88.Pp 89The second field, 90.Pq Fa fs_file , 91describes the mount point for the filesystem. 92For swap and dump partitions, this field should be specified as 93.Dq none . 94.Pp 95The third field, 96.Pq Fa fs_vfstype , 97describes the type of the filesystem. 98The system currently supports these filesystems: 99.Bl -tag -width indent -offset indent 100.It Em adosfs 101an 102.Tn AmigaDOS 103filesystem 104.It Em cd9660 105an 106.Tn ISO 1079660 CD-ROM filesystem 108.It Em ext2fs 109an implementation of the Linux 110.Dq Second Extended File-system . 111.It Em fdesc 112an implementation of /dev/fd 113.It Em ffs 114a local 115.Ux 116filesystem 117.It Em kernfs 118various and sundry kernel statistics 119.It Em lfs 120a log-structured file-system. Currently does not work. 121.It Em mfs 122a local memory-based 123.Ux 124filesystem 125.It Em msdos 126an 127.Tn MS-DOS 128.Dq FAT filesystem 129.It Em nfs 130a Sun Microsystems compatible 131.Dq Network File System 132.It Em null 133a loop-back filesystem, allowing parts of the system to be viewed 134elsewhere. 135.It Em portal 136a general filesystem interface, currently supports TCP and FS mounts. 137.It Em procfs 138a local filesystem of process information 139.It Em swap 140a disk partition to be used for swapping and paging 141.It Em umap 142a user and group re-mapping filesystem. 143.It Em union 144a translucent filesystem 145.El 146.Pp 147The fourth field, 148.Pq Fa fs_mntops , 149describes the mount options associated with the filesystem. 150It is formatted as a comma separated list of options. 151It contains at least the type of mount (see 152.Fa fs_type 153below) plus any additional options 154appropriate to the filesystem type. 155.Pp 156The option 157.Dq auto 158can be used in the 159.Dq noauto 160form to cause 161a file system not to be mounted automatically (with 162.Dq mount -a 163, 164or system boot time). 165.Pp 166If the options 167.Dq userquota 168and/or 169.Dq groupquota 170are specified, 171the filesystem is automatically processed by the 172.Xr quotacheck 8 173command, and user and/or group disk quotas are enabled with 174.Xr quotaon 8 . 175By default, 176filesystem quotas are maintained in files named 177.Pa quota.user 178and 179.Pa quota.group 180which are located at the root of the associated filesystem. 181These defaults may be overridden by putting an equal sign 182and an alternative absolute pathname following the quota option. 183Thus, if the user quota file for 184.Pa /tmp 185is stored in 186.Pa /var/quotas/tmp.user , 187this location can be specified as: 188.Bd -literal -offset indent 189userquota=/var/quotas/tmp.user 190.Ed 191.Pp 192The type of the mount is extracted from the 193.Fa fs_mntops 194field and stored separately in the 195.Fa fs_type 196field (it is not deleted from the 197.Fa fs_mntops 198field). 199If 200.Fa fs_type 201is 202.Dq rw 203or 204.Dq ro 205then the filesystem whose name is given in the 206.Fa fs_file 207field is normally mounted read-write or read-only on the 208specified special file. 209If 210.Fa fs_type 211is 212.Dq sw 213or 214.Dq dp 215then the special file is made available as a piece of swap 216or dump 217space by the 218.Xr swapctl 8 219command towards the beginning of the system reboot procedure. 220See 221.Xr swapctl 8 222for more information on configuring swap and dump devices. 223The fields other than 224.Fa fs_spec 225and 226.Fa fs_type 227are unused. 228If 229.Fa fs_type 230is specified as 231.Dq xx 232the entry is ignored. 233This is useful to show disk partitions which are currently unused. 234.Pp 235The fifth field, 236.Pq Fa fs_freq , 237is used for these filesystems by the 238.Xr dump 8 239command to determine which filesystems need to be dumped. 240If the fifth field is not present, a value of zero is returned and 241.Xr dump 8 242will assume that the filesystem does not need to be dumped. 243.Pp 244The sixth field, 245.Pq Fa fs_passno , 246is used by the 247.Xr fsck 8 248program to determine the order in which filesystem checks are done 249at reboot time. 250The root filesystem should be specified with a 251.Fa fs_passno 252of 1, and other filesystems should have a 253.Fa fs_passno 254of 2. 255Filesystems within a drive will be checked sequentially, 256but filesystems on different drives will be checked at the 257same time to utilize parallelism available in the hardware. 258If the sixth field is not present or zero, 259a value of zero is returned and 260.Xr fsck 8 261will assume that the filesystem does not need to be checked. 262.Bd -literal 263#define FSTAB_RW "rw" /* read-write device */ 264#define FSTAB_RO "ro" /* read-only device */ 265#define FSTAB_SW "sw" /* swap device */ 266#define FSTAB_DP "dp" /* dump device */ 267#define FSTAB_XX "xx" /* ignore totally */ 268 269struct fstab { 270 char *fs_spec; /* block special device name */ 271 char *fs_file; /* filesystem path prefix */ 272 char *fs_vfstype; /* type of filesystem */ 273 char *fs_mntops; /* comma separated mount options */ 274 char *fs_type; /* rw, ro, sw, or xx */ 275 int fs_freq; /* dump frequency, in days */ 276 int fs_passno; /* pass number on parallel fsck */ 277}; 278.Ed 279.Pp 280The proper way to read records from 281.Pa fstab 282is to use the routines 283.Xr getfsent 3 , 284.Xr getfsspec 3 , 285.Xr getfstype 3 , 286and 287.Xr getfsfile 3 . 288.Sh FILES 289.Bl -tag -width /etc/fstab -compact 290.It Pa /etc/fstab 291The file 292.Nm 293resides in 294.Pa /etc . 295.El 296.Sh SEE ALSO 297.Xr getfsent 3 , 298.Xr mount_ados 8 , 299.Xr mount_cd9660 8 , 300.Xr mount_ext2fs 8 , 301.Xr mount_fdesc 8 , 302.Xr mount_ffs 8 , 303.Xr mount_kernfs 8 , 304.Xr mount_lfs 8 , 305.Xr mount_mfs 8 , 306.Xr mount_msdos 8 , 307.Xr mount_nfs 8 , 308.Xr mount_null 8 , 309.Xr mount_portal 8 , 310.Xr mount_procfs 8 , 311.Xr mount_ufs 8 , 312.Xr mount_umap 8 , 313.Xr mount_union 8 , 314.Xr swapctl 8 315.Sh HISTORY 316The 317.Nm 318file format appeared in 319.Bx 4.0 . 320