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Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)fstab.5 8.1 (Berkeley) 6/5/93 29.\" $FreeBSD: src/share/man/man5/fstab.5,v 1.11.2.8 2003/02/10 12:21:08 des Exp $ 30.\" $DragonFly: src/share/man/man5/fstab.5,v 1.5 2008/07/27 21:16:00 thomas Exp $ 31.\" 32.Dd September 13, 2009 33.Dt FSTAB 5 34.Os 35.Sh NAME 36.Nm fstab 37.Nd static information about the file systems 38.Sh SYNOPSIS 39.In fstab.h 40.Sh DESCRIPTION 41The file 42.Nm 43contains descriptive information about the various file 44systems. 45.Nm 46is only read by programs, and not written; 47it is the duty of the system administrator to properly create 48and maintain this file. 49Each file system is described on a separate line; 50fields on each line are separated by tabs or spaces. 51The order of records in 52.Nm 53is important because 54.Xr fsck 8 , 55.Xr mount 8 , 56and 57.Xr umount 8 58sequentially iterate through 59.Nm 60doing their thing. 61.Pp 62The first field, 63.Pq Fa fs_spec , 64describes the special file or 65remote file system to be mounted. 66This may be a 67.Pa /dev/<path> , 68a label from a 69.Xr devtab 5 70(typically 71.Pa /etc/devtab ) , 72or a 73.Pa <host>:<path> 74for NFS. 75Note that 76.Xr devtab 5 77labels maybe augmented with a 78.Pa .suffix 79trailer. 80For example 81.Pa mydisk.s1a . 82Also note 83.Pa /dev 84based paths can mount serial numbers similar to 85.Xr devtab 5 86labels by using the path 87.Pa /dev/serno/SERIALNO[.suffix] . 88.Pp 89The second field, 90.Pq Fa fs_file , 91describes the mount point for the file system. 92For swap partitions, this field should be specified as 93.Dq none . 94.Pp 95The third field, 96.Pq Fa fs_vfstype , 97describes the type of the file system. 98The system can support various file system types. 99Only the root, 100.Pa /usr , 101and 102.Pa /tmp 103file systems need be statically 104compiled into the kernel; 105everything else will be automatically loaded at mount 106time. 107(Exception: the UFS family - FFS, MFS, and LFS cannot 108currently be demand-loaded.) Some people still prefer to statically 109compile other file systems as well. 110.Pp 111The most common file system types are: 112.Bl -tag -width indent -offset indent 113.It Em HAMMER 114a local 115.Xr HAMMER 5 116file system 117.It Em ufs 118a local 119.Xr ffs 5 120.Ux 121file system 122.It Em mfs 123a local memory-based 124.Ux 125file system 126.It Em nfs 127a Sun Microsystems compatible 128.Dq "Network File System" 129.It Em swap 130a disk partition to be used for swapping 131.It Em msdos 132a local 133.Xr msdos 5 134DOS compatible file system 135.It Em cd9660 136a local CD-ROM file system (as per ISO 9660) 137.\" maybe also say Rock Ridge extensions are handled ? 138.It Em procfs 139a file system for accessing process data 140.El 141.Pp 142The fourth field, 143.Pq Fa fs_mntops , 144describes the mount options associated with the file system. 145It is formatted as a comma separated list of options. 146It contains at least the type of mount (see 147.Fa fs_type 148below) plus any additional options 149appropriate to the file system type. 150See the options flag 151.Pq Fl o 152in the 153.Xr mount 8 154page and the file system specific page, such as 155.Xr mount_nfs 8 , 156for additional options that may be specified. 157.Pp 158If the options ``userquota'' and/or ``groupquota'' are specified, 159the file system is automatically processed by the 160.Xr quotacheck 8 161command, and user and/or group disk quotas are enabled with 162.Xr quotaon 8 . 163By default, 164file system quotas are maintained in files named 165.Pa quota.user 166and 167.Pa quota.group 168which are located at the root of the associated file system. 169These defaults may be overridden by putting an equal sign 170and an alternative absolute pathname following the quota option. 171Thus, if the user quota file for 172.Pa /tmp 173is stored in 174.Pa /var/quotas/tmp.user , 175this location can be specified as: 176.Bd -literal -offset indent 177userquota=/var/quotas/tmp.user 178.Ed 179.Pp 180If the option ``noauto'' is specified, the file system will not be automatically 181mounted at system startup. 182This is recommended for all remote file systems other than NFS, 183since only NFS mounts are delayed until after network initialization 184by the 185.Xr rc 8 186startup scripts. 187.Pp 188The type of the mount is extracted from the 189.Fa fs_mntops 190field and stored separately in the 191.Fa fs_type 192field (it is not deleted from the 193.Fa fs_mntops 194field). 195If 196.Fa fs_type 197is ``rw'' or ``ro'' then the file system whose name is given in the 198.Fa fs_file 199field is normally mounted read-write or read-only on the 200specified special file. 201If 202.Fa fs_type 203is ``sw'' then the special file is made available as a piece of swap 204space by the 205.Xr swapon 8 206command at the end of the system reboot procedure. 207The fields other than 208.Fa fs_spec 209and 210.Fa fs_type 211are unused. 212If 213.Fa fs_type 214is specified as ``xx'' the entry is ignored. 215This is useful to show disk partitions which are currently unused. 216.Pp 217The fifth field, 218.Pq Fa fs_freq , 219is used for these file systems by the 220.Xr dump 8 221command to determine which file systems need to be dumped. 222If the fifth field is not present, a value of zero is returned and 223.Nm dump 224will assume that the file system does not need to be dumped. 225.Pp 226The sixth field, 227.Pq Fa fs_passno , 228is used by the 229.Xr fsck 8 230program to determine the order in which file system checks are done 231at reboot time. 232The root file system should be specified with a 233.Fa fs_passno 234of 1, and other file systems should have a 235.Fa fs_passno 236of 2. 237File systems within a drive will be checked sequentially, 238but file systems on different drives will be checked at the 239same time to utilize parallelism available in the hardware. 240If the sixth field is not present or is zero, 241a value of zero is returned and 242.Xr fsck 8 243will assume that the file system does not need to be checked. 244.Bd -literal 245#define FSTAB_RW "rw" /* read/write device */ 246#define FSTAB_RQ "rq" /* read/write with quotas */ 247#define FSTAB_RO "ro" /* read-only device */ 248#define FSTAB_SW "sw" /* swap device */ 249#define FSTAB_XX "xx" /* ignore totally */ 250 251struct fstab { 252 char *fs_spec; /* block special device name */ 253 char *fs_file; /* file system path prefix */ 254 char *fs_vfstype; /* File system type, ufs, nfs */ 255 char *fs_mntops; /* Mount options ala -o */ 256 char *fs_type; /* FSTAB_* from fs_mntops */ 257 int fs_freq; /* dump frequency, in days */ 258 int fs_passno; /* pass number on parallel fsck */ 259}; 260.Ed 261.Pp 262The proper way to read records from 263.Nm 264is to use the routines 265.Xr getfsent 3 , 266.Xr getfsspec 3 , 267.Xr getfstype 3 , 268and 269.Xr getfsfile 3 . 270.Sh FILES 271.Bl -tag -width /etc/fstab -compact 272.It Pa /etc/fstab 273The file 274.Nm 275resides in 276.Pa /etc . 277.El 278.Sh SEE ALSO 279.Xr getfsent 3 , 280.Xr getvfsbyname 3 , 281.Xr HAMMER 5 , 282.Xr dump 8 , 283.Xr fsck 8 , 284.Xr mount 8 , 285.Xr quotacheck 8 , 286.Xr quotaon 8 , 287.Xr swapon 8 , 288.Xr umount 8 289.Sh HISTORY 290The 291.Nm 292file format appeared in 293.Bx 4.0 . 294