.\" $NetBSD: fstab.5,v 1.18 2000/07/05 15:45:35 msaitoh Exp $ .\" .\" Copyright (c) 1980, 1989, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 .\" .Dd June 5, 1993 .Dt FSTAB 5 .Os .Sh NAME .Nm fstab .Nd filesystem table for devices, types, and mount points .Sh SYNOPSIS .Fd #include .Sh DESCRIPTION The file .Nm contains descriptive information about the various file systems. .Nm is only read by programs, and not written; it is the duty of the system administrator to properly create and maintain this file. Each filesystem is described on a separate line; fields on each line are separated by tabs or spaces. Lines beginning with .Dq # are comments. The order of records in .Nm is important because .Xr fsck 8 , .Xr mount 8 , and .Xr umount 8 sequentially iterate through .Nm doing their respective tasks. .Pp The first field, .Pq Fa fs_spec , describes the block special device or remote filesystem to be mounted. For filesystems of type .Em ffs , the special file name is the block special file name, and not the character special file name. If a program needs the character special file name, the program must create it by appending a .Dq r after the last .Dq / in the special file name. .Pp The second field, .Pq Fa fs_file , describes the mount point for the filesystem. For swap and dump partitions, this field should be specified as .Dq none . .Pp The third field, .Pq Fa fs_vfstype , describes the type of the filesystem. The system currently supports these filesystems: .Bl -tag -width indent -offset indent .It Em adosfs an .Tn AmigaDOS filesystem .It Em cd9660 an .Tn ISO 9660 CD-ROM filesystem .It Em ext2fs an implementation of the Linux .Dq Second Extended File-system . .It Em fdesc an implementation of /dev/fd .It Em ffs a local .Ux filesystem .It Em kernfs various and sundry kernel statistics .It Em lfs a log-structured file-system. Currently does not work. .It Em mfs a local memory-based .Ux filesystem .It Em msdos an .Tn MS-DOS .Dq FAT filesystem .It Em nfs a Sun Microsystems compatible .Dq Network File System .It Em null a loop-back filesystem, allowing parts of the system to be viewed elsewhere. .It Em portal a general filesystem interface, currently supports TCP and FS mounts. .It Em procfs a local filesystem of process information .It Em swap a disk partition to be used for swapping and paging .It Em umap a user and group re-mapping filesystem. .It Em union a translucent filesystem .El .Pp The fourth field, .Pq Fa fs_mntops , describes the mount options associated with the filesystem. It is formatted as a comma separated list of options. It contains at least the type of mount (see .Fa fs_type below) plus any additional options appropriate to the filesystem type. .Pp The option .Dq auto can be used in the .Dq noauto form to cause a file system not to be mounted automatically (with .Dq mount -a , or system boot time). .Pp If the options .Dq userquota and/or .Dq groupquota are specified, the filesystem is automatically processed by the .Xr quotacheck 8 command, and user and/or group disk quotas are enabled with .Xr quotaon 8 . By default, filesystem quotas are maintained in files named .Pa quota.user and .Pa quota.group which are located at the root of the associated filesystem. These defaults may be overridden by putting an equal sign and an alternative absolute pathname following the quota option. Thus, if the user quota file for .Pa /tmp is stored in .Pa /var/quotas/tmp.user , this location can be specified as: .Bd -literal -offset indent userquota=/var/quotas/tmp.user .Ed .Pp The type of the mount is extracted from the .Fa fs_mntops field and stored separately in the .Fa fs_type field (it is not deleted from the .Fa fs_mntops field). If .Fa fs_type is .Dq rw or .Dq ro then the filesystem whose name is given in the .Fa fs_file field is normally mounted read-write or read-only on the specified special file. If .Fa fs_type is .Dq sw or .Dq dp then the special file is made available as a piece of swap or dump space by the .Xr swapctl 8 command towards the beginning of the system reboot procedure. See .Xr swapctl 8 for more information on configuring swap and dump devices. The fields other than .Fa fs_spec and .Fa fs_type are unused. If .Fa fs_type is specified as .Dq xx the entry is ignored. This is useful to show disk partitions which are currently unused. .Pp The fifth field, .Pq Fa fs_freq , is used for these filesystems by the .Xr dump 8 command to determine which filesystems need to be dumped. If the fifth field is not present, a value of zero is returned and .Xr dump 8 will assume that the filesystem does not need to be dumped. .Pp The sixth field, .Pq Fa fs_passno , is used by the .Xr fsck 8 program to determine the order in which filesystem checks are done at reboot time. The root filesystem should be specified with a .Fa fs_passno of 1, and other filesystems should have a .Fa fs_passno of 2. Filesystems within a drive will be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the hardware. If the sixth field is not present or zero, a value of zero is returned and .Xr fsck 8 will assume that the filesystem does not need to be checked. .Bd -literal #define FSTAB_RW "rw" /* read-write device */ #define FSTAB_RO "ro" /* read-only device */ #define FSTAB_SW "sw" /* swap device */ #define FSTAB_DP "dp" /* dump device */ #define FSTAB_XX "xx" /* ignore totally */ struct fstab { char *fs_spec; /* block special device name */ char *fs_file; /* filesystem path prefix */ char *fs_vfstype; /* type of filesystem */ char *fs_mntops; /* comma separated mount options */ char *fs_type; /* rw, ro, sw, or xx */ int fs_freq; /* dump frequency, in days */ int fs_passno; /* pass number on parallel fsck */ }; .Ed .Pp The proper way to read records from .Pa fstab is to use the routines .Xr getfsent 3 , .Xr getfsspec 3 , .Xr getfstype 3 , and .Xr getfsfile 3 . .Sh FILES .Bl -tag -width /etc/fstab -compact .It Pa /etc/fstab The file .Nm resides in .Pa /etc . .El .Sh SEE ALSO .Xr getfsent 3 , .Xr mount_ados 8 , .Xr mount_cd9660 8 , .Xr mount_ext2fs 8 , .Xr mount_fdesc 8 , .Xr mount_ffs 8 , .Xr mount_kernfs 8 , .Xr mount_lfs 8 , .Xr mount_mfs 8 , .Xr mount_msdos 8 , .Xr mount_nfs 8 , .Xr mount_null 8 , .Xr mount_portal 8 , .Xr mount_procfs 8 , .Xr mount_ufs 8 , .Xr mount_umap 8 , .Xr mount_union 8 , .Xr swapctl 8 .Sh HISTORY The .Nm file format appeared in .Bx 4.0 .