315 lines
8.1 KiB
Groff
315 lines
8.1 KiB
Groff
.\" $NetBSD: fstab.5,v 1.16 1999/03/17 20:19:45 garbled Exp $
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.\"
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.\" Copyright (c) 1980, 1989, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93
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.\"
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.Dd June 5, 1993
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.Dt FSTAB 5
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.Os
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.Sh NAME
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.Nm fstab
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.Nd filesystem table for devices, types, and mount points
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.Sh SYNOPSIS
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.Fd #include <fstab.h>
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.Sh DESCRIPTION
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The file
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.Nm
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contains descriptive information about the various file systems.
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.Nm
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is only read by programs, and not written;
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it is the duty of the system administrator to properly create
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and maintain this file.
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Each filesystem is described on a separate line;
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fields on each line are separated by tabs or spaces. Lines beginning
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with
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.Dq #
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are comments.
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The order of records in
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.Nm
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is important because
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.Xr fsck 8 ,
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.Xr mount 8 ,
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and
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.Xr umount 8
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sequentially iterate through
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.Nm
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doing their respective tasks.
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.Pp
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The first field,
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.Pq Fa fs_spec ,
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describes the block special device or
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remote filesystem to be mounted.
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For filesystems of type
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.Em ffs ,
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the special file name is the block special file name,
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and not the character special file name.
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If a program needs the character special file name,
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the program must create it by appending a
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.Dq r
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after the
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last
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.Dq /
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in the special file name.
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.Pp
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The second field,
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.Pq Fa fs_file ,
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describes the mount point for the filesystem.
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For swap and dump partitions, this field should be specified as
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.Dq none .
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.Pp
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The third field,
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.Pq Fa fs_vfstype ,
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describes the type of the filesystem.
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The system currently supports these filesystems:
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.Bl -tag -width indent -offset indent
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.It Em adosfs
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an
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.Tn AmigaDOS
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filesystem
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.It Em cd9660
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an
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.Tn ISO
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9660 CD-ROM filesystem
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.It Em ext2fs
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an implementation of the Linux
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.Dq Second Extended File-system .
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.It Em fdesc
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an implementation of /dev/fd
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.It Em ffs
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a local
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.Ux
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filesystem
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.It Em kernfs
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various and sundry kernel statistics
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.It Em lfs
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a log-structured file-system. Currently does not work.
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.It Em mfs
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a local memory-based
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.Ux
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filesystem
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.It Em msdos
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an
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.Tn MS-DOS
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.Dq FAT filesystem
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.It Em nfs
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a Sun Microsystems compatible
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.Dq Network File System
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.It Em nullfs
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a loop-back filesystem, allowing parts of the system to be viewed
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elsewhere.
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.It Em portal
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a general filesystem interface, currently supports TCP and FS mounts.
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.It Em procfs
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a local filesystem of process information
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.It Em swap
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a disk partition to be used for swapping and paging
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.It Em umap
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a user and group re-mapping filesystem.
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.It Em union
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a translucent filesystem
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.El
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.Pp
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The fourth field,
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.Pq Fa fs_mntops ,
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describes the mount options associated with the filesystem.
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It is formatted as a comma separated list of options.
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It contains at least the type of mount (see
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.Fa fs_type
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below) plus any additional options
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appropriate to the filesystem type.
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.Pp
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The option
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.Dq auto
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can be used in the
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.Dq noauto
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form to cause
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a file system not to be mounted automatically (with
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.Dq mount -a
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,
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or system boot time).
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.Pp
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If the options
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.Dq userquota
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and/or
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.Dq groupquota
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are specified,
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the filesystem is automatically processed by the
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.Xr quotacheck 8
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command, and user and/or group disk quotas are enabled with
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.Xr quotaon 8 .
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By default,
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filesystem quotas are maintained in files named
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.Pa quota.user
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and
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.Pa quota.group
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which are located at the root of the associated filesystem.
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These defaults may be overridden by putting an equal sign
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and an alternative absolute pathname following the quota option.
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Thus, if the user quota file for
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.Pa /tmp
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is stored in
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.Pa /var/quotas/tmp.user ,
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this location can be specified as:
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.Bd -literal -offset indent
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userquota=/var/quotas/tmp.user
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.Ed
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.Pp
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The type of the mount is extracted from the
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.Fa fs_mntops
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field and stored separately in the
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.Fa fs_type
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field (it is not deleted from the
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.Fa fs_mntops
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field).
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If
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.Fa fs_type
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is
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.Dq rw
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or
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.Dq ro
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then the filesystem whose name is given in the
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.Fa fs_file
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field is normally mounted read-write or read-only on the
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specified special file.
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If
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.Fa fs_type
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is
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.Dq sw
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or
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.Dq dp
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then the special file is made available as a piece of swap
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or dump
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space by the
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.Xr swapctl 8
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command towards the beginning of the system reboot procedure.
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See
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.Xr swapctl 8
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for more information on configuring swap and dump devices.
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The fields other than
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.Fa fs_spec
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and
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.Fa fs_type
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are unused.
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If
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.Fa fs_type
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is specified as
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.Dq xx
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the entry is ignored.
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This is useful to show disk partitions which are currently unused.
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.Pp
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The fifth field,
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.Pq Fa fs_freq ,
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is used for these filesystems by the
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.Xr dump 8
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command to determine which filesystems need to be dumped.
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If the fifth field is not present, a value of zero is returned and
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.Xr dump 8
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will assume that the filesystem does not need to be dumped.
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.Pp
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The sixth field,
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.Pq Fa fs_passno ,
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is used by the
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.Xr fsck 8
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program to determine the order in which filesystem checks are done
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at reboot time.
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The root filesystem should be specified with a
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.Fa fs_passno
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of 1, and other filesystems should have a
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.Fa fs_passno
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of 2.
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Filesystems within a drive will be checked sequentially,
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but filesystems on different drives will be checked at the
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same time to utilize parallelism available in the hardware.
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If the sixth field is not present or zero,
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a value of zero is returned and
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.Xr fsck 8
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will assume that the filesystem does not need to be checked.
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.Bd -literal
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#define FSTAB_RW "rw" /* read-write device */
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#define FSTAB_RO "ro" /* read-only device */
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#define FSTAB_SW "sw" /* swap device */
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#define FSTAB_DP "dp" /* dump device */
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#define FSTAB_XX "xx" /* ignore totally */
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struct fstab {
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char *fs_spec; /* block special device name */
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char *fs_file; /* filesystem path prefix */
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char *fs_vfstype; /* type of filesystem */
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char *fs_mntops; /* comma separated mount options */
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char *fs_type; /* rw, ro, sw, or xx */
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int fs_freq; /* dump frequency, in days */
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int fs_passno; /* pass number on parallel fsck */
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};
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.Ed
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.Pp
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The proper way to read records from
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.Pa fstab
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is to use the routines
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.Xr getfsent 3 ,
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.Xr getfsspec 3 ,
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.Xr getfstype 3 ,
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and
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.Xr getfsfile 3 .
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.Sh FILES
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.Bl -tag -width /etc/fstab -compact
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.It Pa /etc/fstab
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The file
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.Nm
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resides in
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.Pa /etc .
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.El
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.Sh SEE ALSO
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.Xr getfsent 3 ,
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.Xr mount_ados 8 ,
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.Xr mount_cd9660 8 ,
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.Xr mount_ext2fs 8 ,
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.Xr mount_fdesc 8 ,
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.Xr mount_ffs 8 ,
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.Xr mount_kernfs 8 ,
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.Xr mount_lfs 8 ,
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.Xr mount_mfs 8 ,
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.Xr mount_msdos 8 ,
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.Xr mount_nfs 8 ,
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.Xr mount_null 8 ,
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.Xr mount_portal 8 ,
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.Xr mount_procfs 8 ,
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.Xr mount_ufs 8 ,
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.Xr mount_umap 8 ,
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.Xr mount_union 8 ,
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.Xr swapctl 8 .
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.Sh HISTORY
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The
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.Nm
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file format appeared in
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.Bx 4.0 .
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