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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. This may be a /dev/<path>, a label 70from a devtab (typically /etc/devtab), or a host:path for NFS. 71Note that devtab labels maybe augmented with a ".suffix" trailer. For 72example "mydisk.s1a". 73Also note /dev based paths can mount serial numbers similar to devtab 74labels by using the path "/dev/serno/SERIALNO[.suffix]". 75.Pp 76The second field, 77.Pq Fa fs_file , 78describes the mount point for the file system. 79For swap partitions, this field should be specified as 80.Dq none . 81.Pp 82The third field, 83.Pq Fa fs_vfstype , 84describes the type of the file system. 85The system can support various file system types. 86Only the root, 87.Pa /usr , 88and 89.Pa /tmp 90file systems need be statically 91compiled into the kernel; 92everything else will be automatically loaded at mount 93time. (Exception: the UFS family - FFS, MFS, and LFS cannot 94currently be demand-loaded.) Some people still prefer to statically 95compile other file systems as well. 96.Pp 97The most common file system types are: 98.Bl -tag -width indent -offset indent 99.It Em HAMMER 100a local 101.Xr HAMMER 5 102file system 103.It Em ufs 104a local 105.Xr ffs 5 106.Ux 107file system 108.It Em mfs 109a local memory-based 110.Ux 111file system 112.It Em nfs 113a Sun Microsystems compatible 114.Dq "Network File System" 115.It Em swap 116a disk partition to be used for swapping 117.It Em msdos 118a local 119.Xr msdos 5 120DOS compatible file system 121.It Em cd9660 122a local CD-ROM file system (as per ISO 9660) 123.\" maybe also say Rock Ridge extensions are handled ? 124.It Em procfs 125a file system for accessing process data 126.El 127.Pp 128The fourth field, 129.Pq Fa fs_mntops , 130describes the mount options associated with the file system. 131It is formatted as a comma separated list of options. 132It contains at least the type of mount (see 133.Fa fs_type 134below) plus any additional options 135appropriate to the file system type. See the options flag 136.Pq Fl o 137in the 138.Xr mount 8 139page and the file system specific page, such as 140.Xr mount_nfs 8 , 141for additional options that may be specified. 142.Pp 143If the options ``userquota'' and/or ``groupquota'' are specified, 144the file system is automatically processed by the 145.Xr quotacheck 8 146command, and user and/or group disk quotas are enabled with 147.Xr quotaon 8 . 148By default, 149file system quotas are maintained in files named 150.Pa quota.user 151and 152.Pa quota.group 153which are located at the root of the associated file system. 154These defaults may be overridden by putting an equal sign 155and an alternative absolute pathname following the quota option. 156Thus, if the user quota file for 157.Pa /tmp 158is stored in 159.Pa /var/quotas/tmp.user , 160this location can be specified as: 161.Bd -literal -offset indent 162userquota=/var/quotas/tmp.user 163.Ed 164.Pp 165If the option ``noauto'' is specified, the file system will not be automatically 166mounted at system startup. 167This is recommended for all remote file systems other than NFS, 168since only NFS mounts are delayed until after network initialization 169by the 170.Xr rc 8 171startup scripts. 172.Pp 173The type of the mount is extracted from the 174.Fa fs_mntops 175field and stored separately in the 176.Fa fs_type 177field (it is not deleted from the 178.Fa fs_mntops 179field). 180If 181.Fa fs_type 182is ``rw'' or ``ro'' then the file system whose name is given in the 183.Fa fs_file 184field is normally mounted read-write or read-only on the 185specified special file. 186If 187.Fa fs_type 188is ``sw'' then the special file is made available as a piece of swap 189space by the 190.Xr swapon 8 191command at the end of the system reboot procedure. 192The fields other than 193.Fa fs_spec 194and 195.Fa fs_type 196are unused. 197If 198.Fa fs_type 199is specified as ``xx'' the entry is ignored. 200This is useful to show disk partitions which are currently unused. 201.Pp 202The fifth field, 203.Pq Fa fs_freq , 204is used for these file systems by the 205.Xr dump 8 206command to determine which file systems need to be dumped. 207If the fifth field is not present, a value of zero is returned and 208.Nm dump 209will assume that the file system does not need to be dumped. 210.Pp 211The sixth field, 212.Pq Fa fs_passno , 213is used by the 214.Xr fsck 8 215program to determine the order in which file system checks are done 216at reboot time. 217The root file system should be specified with a 218.Fa fs_passno 219of 1, and other file systems should have a 220.Fa fs_passno 221of 2. 222File systems within a drive will be checked sequentially, 223but file systems on different drives will be checked at the 224same time to utilize parallelism available in the hardware. 225If the sixth field is not present or is zero, 226a value of zero is returned and 227.Xr fsck 8 228will assume that the file system does not need to be checked. 229.Bd -literal 230#define FSTAB_RW "rw" /* read/write device */ 231#define FSTAB_RQ "rq" /* read/write with quotas */ 232#define FSTAB_RO "ro" /* read-only device */ 233#define FSTAB_SW "sw" /* swap device */ 234#define FSTAB_XX "xx" /* ignore totally */ 235 236struct fstab { 237 char *fs_spec; /* block special device name */ 238 char *fs_file; /* file system path prefix */ 239 char *fs_vfstype; /* File system type, ufs, nfs */ 240 char *fs_mntops; /* Mount options ala -o */ 241 char *fs_type; /* FSTAB_* from fs_mntops */ 242 int fs_freq; /* dump frequency, in days */ 243 int fs_passno; /* pass number on parallel fsck */ 244}; 245.Ed 246.Pp 247The proper way to read records from 248.Nm 249is to use the routines 250.Xr getfsent 3 , 251.Xr getfsspec 3 , 252.Xr getfstype 3 , 253and 254.Xr getfsfile 3 . 255.Sh FILES 256.Bl -tag -width /etc/fstab -compact 257.It Pa /etc/fstab 258The file 259.Nm 260resides in 261.Pa /etc . 262.El 263.Sh SEE ALSO 264.Xr getfsent 3 , 265.Xr getvfsbyname 3 , 266.Xr HAMMER 5 , 267.Xr dump 8 , 268.Xr fsck 8 , 269.Xr mount 8 , 270.Xr quotacheck 8 , 271.Xr quotaon 8 , 272.Xr swapon 8 , 273.Xr umount 8 274.Sh HISTORY 275The 276.Nm 277file format appeared in 278.Bx 4.0 . 279