1.\" $NetBSD: fstab.5,v 1.25 2002/05/04 19:50:36 jdolecek 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 \*[Lt]fstab.h\*[Gt] 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 filecore 118a filesystem for 119.Tn RISC\ OS 120.It Em kernfs 121various and sundry kernel statistics 122.It Em lfs 123a log-structured file-system. Currently does not work. 124.It Em mfs 125a local memory-based 126.Ux 127filesystem 128.It Em msdos 129an 130.Tn MS-DOS 131.Dq FAT filesystem 132.It Em nfs 133a Sun Microsystems compatible 134.Dq Network File System 135.It Em ntfs 136a filesystem used by 137.Tn Windows NT . 138Still experimental. 139.It Em null 140a loop-back filesystem, allowing parts of the system to be viewed 141elsewhere. 142.It Em overlay 143a demonstration of layered filesystems. 144.It Em portal 145a general filesystem interface, currently supports TCP and FS mounts. 146.It Em procfs 147a local filesystem of process information 148.It Em swap 149a disk partition to be used for swapping and paging 150.It Em umap 151a user and group re-mapping filesystem. 152.It Em union 153a translucent filesystem 154.El 155.Pp 156The fourth field, 157.Pq Fa fs_mntops , 158describes the mount options associated with the filesystem. 159It is formatted as a comma separated list of options. 160It contains at least the type of mount (see 161.Fa fs_type 162below) plus any additional options 163appropriate to the filesystem type. 164.Pp 165The option 166.Dq auto 167can be used in the 168.Dq noauto 169form to cause 170a file system not to be mounted automatically (with 171.Dq mount -a 172, 173or system boot time). 174.Pp 175If the options 176.Dq userquota 177and/or 178.Dq groupquota 179are specified, 180the filesystem is automatically processed by the 181.Xr quotacheck 8 182command, and user and/or group disk quotas are enabled with 183.Xr quotaon 8 . 184By default, 185filesystem quotas are maintained in files named 186.Pa quota.user 187and 188.Pa quota.group 189which are located at the root of the associated filesystem. 190These defaults may be overridden by putting an equal sign 191and an alternative absolute pathname following the quota option. 192Thus, if the user quota file for 193.Pa /tmp 194is stored in 195.Pa /var/quotas/tmp.user , 196this location can be specified as: 197.Bd -literal -offset indent 198userquota=/var/quotas/tmp.user 199.Ed 200.Pp 201The type of the mount is extracted from the 202.Fa fs_mntops 203field and stored separately in the 204.Fa fs_type 205field (it is not deleted from the 206.Fa fs_mntops 207field). 208If 209.Fa fs_type 210is 211.Dq rw 212or 213.Dq ro 214then the filesystem whose name is given in the 215.Fa fs_file 216field is normally mounted read-write or read-only on the 217specified special file. 218If 219.Fa fs_type 220is 221.Dq sw 222or 223.Dq dp 224then the special file is made available as a piece of swap 225or dump 226space by the 227.Xr swapctl 8 228command towards the beginning of the system reboot procedure. 229See 230.Xr swapctl 8 231for more information on configuring swap and dump devices. 232The fields other than 233.Fa fs_spec 234and 235.Fa fs_type 236are unused. 237If 238.Fa fs_type 239is specified as 240.Dq xx 241the entry is ignored. 242This is useful to show disk partitions which are currently unused. 243.Pp 244The fifth field, 245.Pq Fa fs_freq , 246is used for these filesystems by the 247.Xr dump 8 248command to determine which filesystems need to be dumped. 249If the fifth field is not present, a value of zero is returned and 250.Xr dump 8 251will assume that the filesystem does not need to be dumped. 252.Pp 253The sixth field, 254.Pq Fa fs_passno , 255is used by the 256.Xr fsck 8 257program to determine the order in which filesystem checks are done 258at reboot time. 259The root filesystem should be specified with a 260.Fa fs_passno 261of 1, and other filesystems should have a 262.Fa fs_passno 263of 2. 264Filesystems within a drive will be checked sequentially, 265but filesystems on different drives will be checked at the 266same time to utilize parallelism available in the hardware. 267If the sixth field is not present or zero, 268a value of zero is returned and 269.Xr fsck 8 270will assume that the filesystem does not need to be checked. 271.Bd -literal 272#define FSTAB_RW "rw" /* read-write device */ 273#define FSTAB_RO "ro" /* read-only device */ 274#define FSTAB_SW "sw" /* swap device */ 275#define FSTAB_DP "dp" /* dump device */ 276#define FSTAB_XX "xx" /* ignore totally */ 277 278struct fstab { 279 char *fs_spec; /* block special device name */ 280 char *fs_file; /* filesystem path prefix */ 281 char *fs_vfstype; /* type of filesystem */ 282 char *fs_mntops; /* comma separated mount options */ 283 char *fs_type; /* rw, ro, sw, or xx */ 284 int fs_freq; /* dump frequency, in days */ 285 int fs_passno; /* pass number on parallel fsck */ 286}; 287.Ed 288.Pp 289The proper way to read records from 290.Pa fstab 291is to use the routines 292.Xr getfsent 3 , 293.Xr getfsspec 3 , 294.Xr getfstype 3 , 295and 296.Xr getfsfile 3 . 297.Sh FILES 298.Bl -tag -width /etc/fstab 299.It Pa /etc/fstab 300The location of 301.Nm 302configuration file. 303.It Pa /usr/share/examples/fstab/ 304Some useful configuration examples. 305.El 306.Sh SEE ALSO 307.Xr getfsent 3 , 308.Xr mount 8 , 309.Xr swapctl 8 310.Sh HISTORY 311The 312.Nm 313file format appeared in 314.Bx 4.0 . 315