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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 July 27, 2008 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. 70.Pp 71The second field, 72.Pq Fa fs_file , 73describes the mount point for the file system. 74For swap partitions, this field should be specified as 75.Dq none . 76.Pp 77The third field, 78.Pq Fa fs_vfstype , 79describes the type of the file system. 80The system can support various file system types. 81Only the root, 82.Pa /usr , 83and 84.Pa /tmp 85file systems need be statically 86compiled into the kernel; 87everything else will be automatically loaded at mount 88time. (Exception: the UFS family - FFS, MFS, and LFS cannot 89currently be demand-loaded.) Some people still prefer to statically 90compile other file systems as well. 91.Pp 92The most common file system types are: 93.Bl -tag -width indent -offset indent 94.It Em HAMMER 95a local 96.Xr HAMMER 5 97file system 98.It Em ufs 99a local 100.Xr ffs 5 101.Ux 102file system 103.It Em mfs 104a local memory-based 105.Ux 106file system 107.It Em nfs 108a Sun Microsystems compatible 109.Dq "Network File System" 110.It Em swap 111a disk partition to be used for swapping 112.It Em msdos 113a local 114.Xr msdos 5 115DOS compatible file system 116.It Em cd9660 117a local CD-ROM file system (as per ISO 9660) 118.\" maybe also say Rock Ridge extensions are handled ? 119.It Em procfs 120a file system for accessing process data 121.El 122.Pp 123The fourth field, 124.Pq Fa fs_mntops , 125describes the mount options associated with the file system. 126It is formatted as a comma separated list of options. 127It contains at least the type of mount (see 128.Fa fs_type 129below) plus any additional options 130appropriate to the file system type. See the options flag 131.Pq Fl o 132in the 133.Xr mount 8 134page and the file system specific page, such as 135.Xr mount_nfs 8 , 136for additional options that may be specified. 137.Pp 138If the options ``userquota'' and/or ``groupquota'' are specified, 139the file system is automatically processed by the 140.Xr quotacheck 8 141command, and user and/or group disk quotas are enabled with 142.Xr quotaon 8 . 143By default, 144file system quotas are maintained in files named 145.Pa quota.user 146and 147.Pa quota.group 148which are located at the root of the associated file system. 149These defaults may be overridden by putting an equal sign 150and an alternative absolute pathname following the quota option. 151Thus, if the user quota file for 152.Pa /tmp 153is stored in 154.Pa /var/quotas/tmp.user , 155this location can be specified as: 156.Bd -literal -offset indent 157userquota=/var/quotas/tmp.user 158.Ed 159.Pp 160If the option ``noauto'' is specified, the file system will not be automatically 161mounted at system startup. 162This is recommended for all remote file systems other than NFS, 163since only NFS mounts are delayed until after network initialization 164by the 165.Xr rc 8 166startup scripts. 167.Pp 168The type of the mount is extracted from the 169.Fa fs_mntops 170field and stored separately in the 171.Fa fs_type 172field (it is not deleted from the 173.Fa fs_mntops 174field). 175If 176.Fa fs_type 177is ``rw'' or ``ro'' then the file system whose name is given in the 178.Fa fs_file 179field is normally mounted read-write or read-only on the 180specified special file. 181If 182.Fa fs_type 183is ``sw'' then the special file is made available as a piece of swap 184space by the 185.Xr swapon 8 186command at the end of the system reboot procedure. 187The fields other than 188.Fa fs_spec 189and 190.Fa fs_type 191are unused. 192If 193.Fa fs_type 194is specified as ``xx'' the entry is ignored. 195This is useful to show disk partitions which are currently unused. 196.Pp 197The fifth field, 198.Pq Fa fs_freq , 199is used for these file systems by the 200.Xr dump 8 201command to determine which file systems need to be dumped. 202If the fifth field is not present, a value of zero is returned and 203.Nm dump 204will assume that the file system does not need to be dumped. 205.Pp 206The sixth field, 207.Pq Fa fs_passno , 208is used by the 209.Xr fsck 8 210program to determine the order in which file system checks are done 211at reboot time. 212The root file system should be specified with a 213.Fa fs_passno 214of 1, and other file systems should have a 215.Fa fs_passno 216of 2. 217File systems within a drive will be checked sequentially, 218but file systems on different drives will be checked at the 219same time to utilize parallelism available in the hardware. 220If the sixth field is not present or is zero, 221a value of zero is returned and 222.Xr fsck 8 223will assume that the file system does not need to be checked. 224.Bd -literal 225#define FSTAB_RW "rw" /* read/write device */ 226#define FSTAB_RQ "rq" /* read/write with quotas */ 227#define FSTAB_RO "ro" /* read-only device */ 228#define FSTAB_SW "sw" /* swap device */ 229#define FSTAB_XX "xx" /* ignore totally */ 230 231struct fstab { 232 char *fs_spec; /* block special device name */ 233 char *fs_file; /* file system path prefix */ 234 char *fs_vfstype; /* File system type, ufs, nfs */ 235 char *fs_mntops; /* Mount options ala -o */ 236 char *fs_type; /* FSTAB_* from fs_mntops */ 237 int fs_freq; /* dump frequency, in days */ 238 int fs_passno; /* pass number on parallel fsck */ 239}; 240.Ed 241.Pp 242The proper way to read records from 243.Nm 244is to use the routines 245.Xr getfsent 3 , 246.Xr getfsspec 3 , 247.Xr getfstype 3 , 248and 249.Xr getfsfile 3 . 250.Sh FILES 251.Bl -tag -width /etc/fstab -compact 252.It Pa /etc/fstab 253The file 254.Nm 255resides in 256.Pa /etc . 257.El 258.Sh SEE ALSO 259.Xr getfsent 3 , 260.Xr getvfsbyname 3 , 261.Xr HAMMER 5 , 262.Xr dump 8 , 263.Xr fsck 8 , 264.Xr mount 8 , 265.Xr quotacheck 8 , 266.Xr quotaon 8 , 267.Xr swapon 8 , 268.Xr umount 8 269.Sh HISTORY 270The 271.Nm 272file format appeared in 273.Bx 4.0 . 274