1.\" $NetBSD: fstab.5,v 1.42 2012/08/12 17:13:34 wiz 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 31.\" 32.Dd August 12, 2012 33.Dt FSTAB 5 34.Os 35.Sh NAME 36.Nm fstab 37.Nd file system table for devices, types, and mount points 38.Sh SYNOPSIS 39.In fstab.h 40.Sh DESCRIPTION 41The file 42.Nm 43contains descriptive information about the various file systems. 44.Nm 45is only read by programs, and not written; 46it is the duty of the system administrator to properly create 47and maintain this file. 48Each file system is described on a separate line; 49fields on each line are separated by tabs or spaces. 50Lines beginning 51with 52.Dq # 53are comments. 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 respective tasks. 64.Pp 65Each configuration line/record in 66.Nm 67has the format: 68.Dl fs_spec fs_file fs_vfstype fs_mntops fs_freq fs_passno 69.Pp 70The first field, 71.Pq Fa fs_spec , 72describes the block special device or 73remote file system to be mounted. 74For file systems of type 75.Em ffs , 76the special file name is the block special file name, 77and not the character special file name. 78If a program needs the character special file name, 79the program must create it by appending a 80.Dq r 81after the 82last 83.Dq / 84in the special file name. 85.Pp 86If the first field is of the form 87.Dq NAME=<value> 88then all the 89.Xr dk 4 90wedge partitions are searched for one that has a wedge name equal to 91.Ar <value> 92and the device corresponding to it is selected. 93.Pp 94The second field, 95.Pq Fa fs_file , 96describes the mount point for the file system. 97For swap and dump partitions, this field should be specified as 98.Dq none . 99.Pp 100The third field, 101.Pq Fa fs_vfstype , 102describes the type of the file system. 103The system currently supports these file systems: 104.Bl -tag -width filecore -offset indent 105.It Em adosfs 106an 107.Tn AmigaDOS 108file system. 109.It Em cd9660 110an 111.Tn ISO 1129660 CD-ROM file system. 113.It Em ext2fs 114an implementation of the Linux 115.Dq Second Extended File-system . 116.It Em fdesc 117an implementation of 118.Pa /dev/fd . 119.It Em ffs 120a local 121.Ux 122file system. 123.It Em filecore 124a file system for 125.Tn RISC\ OS . 126.It Em kernfs 127various and sundry kernel statistics. 128.It Em lfs 129a log-structured file-system. 130.It Em mfs 131a local memory-based 132.Ux 133file system. 134.It Em msdos 135an 136.Tn MS-DOS 137.Dq FAT file system . 138.It Em nfs 139a Sun Microsystems compatible 140.Dq Network File System . 141.It Em ntfs 142a file system used by 143.Tn Windows NT . 144Still experimental. 145.It Em null 146a loop-back file system, allowing parts of the system to be viewed 147elsewhere. 148.It Em overlay 149a demonstration of layered file systems. 150.It Em portal 151a general file system interface, currently supports TCP and FS mounts. 152.It Em procfs 153a local file system of process information. 154.It Em ptyfs 155a pseudo-terminal device file system. 156.It Em smbfs 157a shared resource from an SMB/CIFS file server. 158.It Em swap 159a disk partition to be used for swapping and paging. 160.It Em tmpfs 161an efficient memory file system. 162.It Em umap 163a user and group re-mapping file system. 164.It Em union 165a translucent file system. 166.El 167.Pp 168The fourth field, 169.Pq Fa fs_mntops , 170describes the mount options associated with the file system. 171It is formatted as a comma separated list of options. 172It contains at least the type of mount (see 173.Fa fs_type 174below) plus any additional options 175appropriate to the file system type. 176.Pp 177The option 178.Dq auto 179can be used in the 180.Dq noauto 181form to cause 182a file system not to be mounted automatically (with 183.Dq mount -a 184, 185or system boot time). 186.Pp 187If the options 188.Dq userquota 189and/or 190.Dq groupquota 191are specified, 192the file system is automatically processed by the 193.Xr quotacheck 8 194command, and legacy user and/or group disk quotas are enabled with 195.Xr quotaon 8 . 196By default, 197file system quotas are maintained in files named 198.Pa quota.user 199and 200.Pa quota.group 201which are located at the root of the associated file system. 202These defaults may be overridden by putting an equal sign 203and an alternative absolute pathname following the quota option. 204Thus, if the user quota file for 205.Pa /tmp 206is stored in 207.Pa /var/quotas/tmp.user , 208this location can be specified as: 209.Bd -literal -offset indent 210userquota=/var/quotas/tmp.user 211.Ed 212.Pp 213It is recommended to turn on the new, in-file system quota with 214.Xr tunefs 8 215or at 216.Xr newfs 8 217time, and to not use the 218.Dq userquota 219or 220.Dq groupquota 221options. 222Migration of limits to the new in-file system quota can be handled 223via 224.Xr quotadump 8 225and 226.Xr quotarestore 8 . 227.Pp 228The option 229.Dq rump 230is used to mount the file system using a 231.Xr rump 3 232userspace server instead of the kernel server. 233.Pp 234The type of the mount is extracted from the 235.Fa fs_mntops 236field and stored separately in the 237.Fa fs_type 238field (it is not deleted from the 239.Fa fs_mntops 240field). 241If 242.Fa fs_type 243is 244.Dq rw 245or 246.Dq ro 247then the file system whose name is given in the 248.Fa fs_file 249field is normally mounted read-write or read-only on the 250specified special file. 251If 252.Fa fs_type 253is 254.Dq sw 255or 256.Dq dp 257then the special file is made available as a piece of swap 258or dump 259space by the 260.Xr swapctl 8 261command towards the beginning of the system reboot procedure. 262See 263.Xr swapctl 8 264for more information on configuring swap and dump devices. 265The fields other than 266.Fa fs_spec 267and 268.Fa fs_type 269are unused. 270If 271.Fa fs_type 272is specified as 273.Dq xx 274the entry is ignored. 275This is useful to show disk partitions which are currently unused. 276.Pp 277The fifth field, 278.Pq Fa fs_freq , 279is used for these file systems by the 280.Xr dump 8 281command to determine which file systems need to be dumped. 282If the fifth field is not present, a value of zero is returned and 283.Xr dump 8 284will assume that the file system does not need to be dumped. 285.Pp 286The sixth field, 287.Pq Fa fs_passno , 288is used by the 289.Xr fsck 8 290program to determine the order in which file system checks are done 291at reboot time. 292The root file system should be specified with a 293.Fa fs_passno 294of 1, and other file systems should have a 295.Fa fs_passno 296of 2. 297Filesystems within a drive will be checked sequentially, 298but file systems on different drives will be checked at the 299same time to use parallelism available in the hardware. 300If the sixth field is not present or zero, 301a value of zero is returned and 302.Xr fsck 8 303will assume that the file system does not need to be checked. 304.Bd -literal 305#define FSTAB_RW "rw" /* read-write device */ 306#define FSTAB_RQ "rq" /* read/write with quotas */ 307#define FSTAB_RO "ro" /* read-only device */ 308#define FSTAB_SW "sw" /* swap device */ 309#define FSTAB_DP "dp" /* dump device */ 310#define FSTAB_XX "xx" /* ignore totally */ 311 312struct fstab { 313 char *fs_spec; /* block special device name */ 314 char *fs_file; /* file system path prefix */ 315 char *fs_vfstype; /* type of file system */ 316 char *fs_mntops; /* comma separated mount options */ 317 char *fs_type; /* rw, ro, sw, or xx */ 318 int fs_freq; /* dump frequency, in days */ 319 int fs_passno; /* pass number on parallel fsck */ 320}; 321.Ed 322.Pp 323The proper way to read records from 324.Pa fstab 325is to use the routines 326.Xr getfsent 3 , 327.Xr getfsspec 3 , 328and 329.Xr getfsfile 3 . 330.Sh FILES 331.Bl -tag -width /etc/fstab 332.It Pa /etc/fstab 333The location of 334.Nm 335configuration file. 336.It Pa /usr/share/examples/fstab/ 337Some useful configuration examples. 338.El 339.Sh EXAMPLES 340To use 341.Dq NAME 342on a non-GPT disk, use: 343.Bd -literal 344NAME=sb2k5Root/a / ffs rw,log 1 1 345NAME=sb2k5Root/b none swap sw,dp 0 0 346.Ed 347For a 348.Xr gpt 8 349disk, use: 350.Bd -literal 351NAME=firstpartition / ffs rw,log 1 1 352NAME=secondpartition none swap sw,dp 0 0 353.Ed 354.Sh SEE ALSO 355.Xr getfsent 3 , 356.Xr getfsspecname 3 , 357.Xr mount 8 , 358.Xr swapctl 8 359.Sh HISTORY 360The 361.Nm 362file format appeared in 363.Bx 4.0 . 364