mount/fstab.5

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  32 .\"     @(#)fstab.5     6.5 (Berkeley) 5/10/91
  33 .\"
  34 .\" Modified Sat Mar  6 20:45:03 1993, faith@cs.unc.edu, for Linux
  35 .\" Sat Oct  9 10:07:10 1993: converted to man format by faith@cs.unc.edu
  36 .\" Sat Nov 20 20:47:38 1993: hpfs documentation added
  37 .\" Sat Nov 27 20:23:32 1993: Updated authorship information
  38 .\" Wed Jul 26 00:00:00 1995: Updated some nfs stuff, joey@infodrom.north.de
  39 .\" Tue Apr  2 00:38:28 1996: added info about "noauto", "user", etc.
  40 .\" Tue Jun 15 20:02:18 1999: added LABEL and UUID
  41 .\"
  42 .TH FSTAB 5 "15 June 1999" "Linux 2.2" "Linux Programmer's Manual"
  43 .SH NAME
  44 fstab \- static information about the filesystems
  45 .SH SYNOPSIS
  46 .B #include <fstab.h>
  47 .SH DESCRIPTION
  48 The file
  49 .B fstab
  50 contains descriptive information about the various file systems.
  51 .B fstab
  52 is only read by programs, and not written; it is the duty of the system
  53 administrator to properly create and maintain this file.  Each filesystem
  54 is described on a separate line; fields on each line are separated by tabs
  55 or spaces.  The order of records in
  56 .B fstab
  57 is important because
  58 .BR fsck (8),
  59 .BR mount (8),
  60 and
  61 .BR umount (8)
  62 sequentially iterate through
  63 .B fstab
  64 doing their thing.
  65
  66 The first field,
  67 .RI ( fs_spec ),
  68 describes the block special device or
  69 remote filesystem to be mounted.
  70 .LP
  71 For ordinary mounts it will hold (a link to) a block special
  72 device node (as created by
  73 .BR mknod (8))
  74 for the device to be mounted, like `/dev/cdrom' or `/dev/sdb7'.
  75 For NFS mounts one will have <host>:<dir>, e.g., `knuth.aeb.nl:/'.
  76 For procfs, use `proc'.
  77 .LP
  78 Instead of giving the device explicitly, one may indicate
  79 the (ext2) filesystem that is to be mounted by its UUID or
  80 volume label (cf.
  81 .BR e2label (8)),
  82 writing LABEL=<label> or UUID=<uuid>,
  83 e.g., `LABEL=Boot' or `UUID=3e6be9de\%-8139\%-11d1\%-9106\%-a43f08d823a6'.
  84 This will make the system more robust: adding or removing a SCSI disk
  85 changes the disk device name but not the filesystem volume label.
  86
  87 The second field,
  88 .RI ( fs_file ),
  89 describes the mount point for the filesystem.  For swap partitions, this
  90 field should be specified as `none'. If the name of the mount point
  91 contains spaces these can be escaped as `\\040'.
  92
  93 The third field,
  94 .RI ( fs_vfstype ),
  95 describes the type of the filesystem.  The system currently supports these
  96 types of filesystems (and possibly others - consult
  97 .IR /proc/filesystems ):
  98 .TP
  99 .I minix
 100 a local filesystem, supporting filenames of length 14 or 30 characters.
 101 .TP
 102 .I ext
 103 a local filesystem with longer filenames and larger inodes.  This
 104 filesystem has been replaced by the
 105 .I ext2
 106 file system, and should no longer be used.
 107 .TP
 108 .I ext2
 109 a local filesystem with longer filenames, larger inodes, and lots of other
 110 features.
 111 .TP
 112 .I xiafs
 113 a local filesystem with longer filenames, larger inodes, and lots of other
 114 features.
 115 .TP
 116 .I msdos
 117 a local filesystem for MS-DOS partitions.
 118 .TP
 119 .I hpfs
 120 a local filesystem for HPFS partitions.
 121 .TP
 122 .I iso9660
 123 a local filesystem used for CD-ROM drives.
 124 .TP
 125 .I nfs
 126 a filesystem for mounting partitions from remote systems.
 127 .TP
 128 .I swap
 129 a disk partition to be used for swapping.
 130 .PP
 131 If
 132 .I fs_vfstype
 133 is specified as ``ignore'' the entry is ignored.  This is useful to show
 134 disk partitions which are currently unused.
 135
 136 The fourth field,
 137 .RI ( fs_mntops ),
 138 describes the mount options associated with the filesystem.
 139
 140 It is formatted as a comma separated list of options.  It contains at least
 141 the type of mount plus any additional options appropriate to the filesystem
 142 type.  For documentation on the available options for non-nfs file systems,
 143 see
 144 .BR mount (8).
 145 For documentation on all nfs-specific options have a look at
 146 .BR nfs (5).
 147 Common for all types of file system are the options ``noauto''
 148 (do not mount when "mount -a" is given, e.g., at boot time),
 149 and ``user'' (allow a user to mount). For more details, see
 150 .BR mount (8).
 151
 152 The fifth field,
 153 .RI ( fs_freq ),
 154 is used for these filesystems by the
 155 .BR dump (8)
 156 command to determine which filesystems need to be dumped.  If the fifth
 157 field is not present, a value of zero is returned and
 158 .B dump
 159 will assume that the filesystem does not need to be dumped.
 160
 161 The sixth field,
 162 .RI ( fs_passno ),
 163 is used by the
 164 .BR fsck (8)
 165 program to determine the order in which filesystem checks are done at
 166 reboot time.  The root filesystem should be specified with a
 167 .I fs_passno
 168 of 1, and other filesystems should have a
 169 .I fs_passno
 170 of 2.  Filesystems within a drive will be checked sequentially, but
 171 filesystems on different drives will be checked at the same time to utilize
 172 parallelism available in the hardware.  If the sixth field is not present
 173 or zero, a value of zero is returned and
 174 .B fsck
 175 will assume that the filesystem does not need to be checked.
 176
 177 The proper way to read records from
 178 .B fstab
 179 is to use the routines
 180 .BR getmntent (3).
 181 .SH FILES
 182 .I /etc/fstab
 183 The file
 184 .B fstab
 185 resides in
 186 .IR /etc .
 187 .SH BUGS
 188 The documentation in
 189 .BR mount (8)
 190 is often more up-to-date.
 191 .SH "SEE ALSO"
 192 .BR getmntent "(3), " mount "(8), " swapon "(8), " nfs (5)
 193 .SH HISTORY
 194 The
 195 .B fstab
 196 file format appeared in 4.0BSD.