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Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 33.\" $FreeBSD: src/share/man/man5/fstab.5,v 1.11.2.8 2003/02/10 12:21:08 des Exp $ 34.\" $DragonFly: src/share/man/man5/fstab.5,v 1.5 2008/07/27 21:16:00 thomas Exp $ 35.\" 36.Dd September 13, 2009 37.Dt FSTAB 5 38.Os 39.Sh NAME 40.Nm fstab 41.Nd static information about the file systems 42.Sh SYNOPSIS 43.In fstab.h 44.Sh DESCRIPTION 45The file 46.Nm 47contains descriptive information about the various file 48systems. 49.Nm 50is only read by programs, and not written; 51it is the duty of the system administrator to properly create 52and maintain this file. 53Each file system is described on a separate line; 54fields on each line are separated by tabs or spaces. 55The order of records in 56.Nm 57is important because 58.Xr fsck 8 , 59.Xr mount 8 , 60and 61.Xr umount 8 62sequentially iterate through 63.Nm 64doing their thing. 65.Pp 66The first field, 67.Pq Fa fs_spec , 68describes the special file or 69remote file system to be mounted. 70This may be a 71.Pa /dev/<path> , 72a label from a 73.Xr devtab 5 74(typically 75.Pa /etc/devtab ) , 76or a 77.Pa <host>:<path> 78for NFS. 79Note that 80.Xr devtab 5 81labels maybe augmented with a 82.Pa .suffix 83trailer. 84For example 85.Pa mydisk.s1a . 86Also note 87.Pa /dev 88based paths can mount serial numbers similar to 89.Xr devtab 5 90labels by using the path 91.Pa /dev/serno/SERIALNO[.suffix] . 92.Pp 93The second field, 94.Pq Fa fs_file , 95describes the mount point for the file system. 96For swap partitions, this field should be specified as 97.Dq none . 98.Pp 99The third field, 100.Pq Fa fs_vfstype , 101describes the type of the file system. 102The system can support various file system types. 103Only the root, 104.Pa /usr , 105and 106.Pa /tmp 107file systems need be statically 108compiled into the kernel; 109everything else will be automatically loaded at mount 110time. 111(Exception: the UFS family - FFS, MFS, and LFS cannot 112currently be demand-loaded.) Some people still prefer to statically 113compile other file systems as well. 114.Pp 115The most common file system types are: 116.Bl -tag -width indent -offset indent 117.It Em HAMMER 118a local 119.Xr HAMMER 5 120file system 121.It Em ufs 122a local 123.Xr ffs 5 124.Ux 125file system 126.It Em mfs 127a local memory-based 128.Ux 129file system 130.It Em nfs 131a Sun Microsystems compatible 132.Dq "Network File System" 133.It Em swap 134a disk partition to be used for swapping 135.It Em msdos 136a local 137.Xr msdos 5 138DOS compatible file system 139.It Em cd9660 140a local CD-ROM file system (as per ISO 9660) 141.\" maybe also say Rock Ridge extensions are handled ? 142.It Em procfs 143a file system for accessing process data 144.El 145.Pp 146The fourth field, 147.Pq Fa fs_mntops , 148describes the mount options associated with the file system. 149It is formatted as a comma separated list of options. 150It contains at least the type of mount (see 151.Fa fs_type 152below) plus any additional options 153appropriate to the file system type. 154See the options flag 155.Pq Fl o 156in the 157.Xr mount 8 158page and the file system specific page, such as 159.Xr mount_nfs 8 , 160for additional options that may be specified. 161.Pp 162If the options ``userquota'' and/or ``groupquota'' are specified, 163the file system is automatically processed by the 164.Xr quotacheck 8 165command, and user and/or group disk quotas are enabled with 166.Xr quotaon 8 . 167By default, 168file system quotas are maintained in files named 169.Pa quota.user 170and 171.Pa quota.group 172which are located at the root of the associated file system. 173These defaults may be overridden by putting an equal sign 174and an alternative absolute pathname following the quota option. 175Thus, if the user quota file for 176.Pa /tmp 177is stored in 178.Pa /var/quotas/tmp.user , 179this location can be specified as: 180.Bd -literal -offset indent 181userquota=/var/quotas/tmp.user 182.Ed 183.Pp 184If the option ``noauto'' is specified, the file system will not be automatically 185mounted at system startup. 186This is recommended for all remote file systems other than NFS, 187since only NFS mounts are delayed until after network initialization 188by the 189.Xr rc 8 190startup scripts. 191.Pp 192The type of the mount is extracted from the 193.Fa fs_mntops 194field and stored separately in the 195.Fa fs_type 196field (it is not deleted from the 197.Fa fs_mntops 198field). 199If 200.Fa fs_type 201is ``rw'' or ``ro'' then the file system whose name is given in the 202.Fa fs_file 203field is normally mounted read-write or read-only on the 204specified special file. 205If 206.Fa fs_type 207is ``sw'' then the special file is made available as a piece of swap 208space by the 209.Xr swapon 8 210command at the end of the system reboot procedure. 211The fields other than 212.Fa fs_spec 213and 214.Fa fs_type 215are unused. 216If 217.Fa fs_type 218is specified as ``xx'' the entry is ignored. 219This is useful to show disk partitions which are currently unused. 220.Pp 221The fifth field, 222.Pq Fa fs_freq , 223is used for these file systems by the 224.Xr dump 8 225command to determine which file systems need to be dumped. 226If the fifth field is not present, a value of zero is returned and 227.Nm dump 228will assume that the file system does not need to be dumped. 229.Pp 230The sixth field, 231.Pq Fa fs_passno , 232is used by the 233.Xr fsck 8 234program to determine the order in which file system checks are done 235at reboot time. 236The root file system should be specified with a 237.Fa fs_passno 238of 1, and other file systems should have a 239.Fa fs_passno 240of 2. 241File systems within a drive will be checked sequentially, 242but file systems on different drives will be checked at the 243same time to utilize parallelism available in the hardware. 244If the sixth field is not present or is zero, 245a value of zero is returned and 246.Xr fsck 8 247will assume that the file system does not need to be checked. 248.Bd -literal 249#define FSTAB_RW "rw" /* read/write device */ 250#define FSTAB_RQ "rq" /* read/write with quotas */ 251#define FSTAB_RO "ro" /* read-only device */ 252#define FSTAB_SW "sw" /* swap device */ 253#define FSTAB_XX "xx" /* ignore totally */ 254 255struct fstab { 256 char *fs_spec; /* block special device name */ 257 char *fs_file; /* file system path prefix */ 258 char *fs_vfstype; /* File system type, ufs, nfs */ 259 char *fs_mntops; /* Mount options ala -o */ 260 char *fs_type; /* FSTAB_* from fs_mntops */ 261 int fs_freq; /* dump frequency, in days */ 262 int fs_passno; /* pass number on parallel fsck */ 263}; 264.Ed 265.Pp 266The proper way to read records from 267.Nm 268is to use the routines 269.Xr getfsent 3 , 270.Xr getfsspec 3 , 271.Xr getfstype 3 , 272and 273.Xr getfsfile 3 . 274.Sh FILES 275.Bl -tag -width /etc/fstab -compact 276.It Pa /etc/fstab 277The file 278.Nm 279resides in 280.Pa /etc . 281.El 282.Sh SEE ALSO 283.Xr getfsent 3 , 284.Xr getvfsbyname 3 , 285.Xr HAMMER 5 , 286.Xr dump 8 , 287.Xr fsck 8 , 288.Xr mount 8 , 289.Xr quotacheck 8 , 290.Xr quotaon 8 , 291.Xr swapon 8 , 292.Xr umount 8 293.Sh HISTORY 294The 295.Nm 296file format appeared in 297.Bx 4.0 . 298