1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. 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.\" $FreeBSD$ 34.\" 35.Dd November 23, 2008 36.Dt FSTAB 5 37.Os 38.Sh NAME 39.Nm fstab 40.Nd static information about the file systems 41.Sh SYNOPSIS 42.In fstab.h 43.Sh DESCRIPTION 44The file 45.Nm 46contains descriptive information about the various file 47systems. 48.Nm 49is only read by programs, and not written; 50it is the duty of the system administrator to properly create 51and maintain this file. 52Each file system is described on a separate line; 53fields on each line are separated by tabs or spaces. 54The order of records in 55.Nm 56is important because 57.Xr fsck 8 , 58.Xr mount 8 , 59and 60.Xr umount 8 61sequentially iterate through 62.Nm 63doing their thing. 64.Pp 65The first field, 66.Pq Fa fs_spec , 67describes the special device or 68remote file system to be mounted. 69.Pp 70The second field, 71.Pq Fa fs_file , 72describes the mount point for the file system. 73For swap partitions, this field should be specified as ``none''. 74.Pp 75The third field, 76.Pq Fa fs_vfstype , 77describes the type of the file system. 78The system can support various file system types. 79Only the root, /usr, and /tmp file systems need be statically 80compiled into the kernel; 81everything else will be automatically loaded at mount 82time. 83(Exception: the UFS family - FFS and LFS cannot 84currently be demand-loaded.) 85Some people still prefer to statically 86compile other file systems as well. 87.Pp 88The fourth field, 89.Pq Fa fs_mntops , 90describes the mount options associated with the file system. 91It is formatted as a comma separated list of options. 92It contains at least the type of mount (see 93.Fa fs_type 94below) plus any additional options appropriate to the file system type. 95See the options flag 96.Pq Fl o 97in the 98.Xr mount 8 99page and the file system specific page, such as 100.Xr mount_nfs 8 , 101for additional options that may be specified. 102All options that can be given to the file system specific mount commands 103can be used in 104.Nm 105as well. 106They just need to be formatted a bit differently. 107The arguments of the 108.Fl o 109option can be used without the preceding 110.Fl o 111flag. 112Other options need both the file system specific flag and its argument, 113separated by an equal sign. 114For example, mounting an 115.Xr msdosfs 5 116filesystem, the options 117.Bd -literal -offset indent 118-o sync -o noatime -m 644 -M 755 -u foo -g bar 119.Ed 120.Pp 121should be written as 122.Bd -literal -offset indent 123sync,noatime,-m=644,-M=755,-u=foo,-g=bar 124.Ed 125.Pp 126in the option field of 127.Nm . 128.Pp 129If the options ``userquota'' and/or ``groupquota'' are specified, 130the file system is automatically processed by the 131.Xr quotacheck 8 132command, and user and/or group disk quotas are enabled with 133.Xr quotaon 8 . 134By default, 135file system quotas are maintained in files named 136.Pa quota.user 137and 138.Pa quota.group 139which are located at the root of the associated file system. 140These defaults may be overridden by putting an equal sign 141and an alternative absolute pathname following the quota option. 142Thus, if the user quota file for 143.Pa /tmp 144is stored in 145.Pa /var/quotas/tmp.user , 146this location can be specified as: 147.Bd -literal -offset indent 148userquota=/var/quotas/tmp.user 149.Ed 150.Pp 151If the option ``noauto'' is specified, the file system will not be automatically 152mounted at system startup. 153Note that, for network file systems 154of third party types 155(i.e., types supported by additional software 156not included in the base system) 157to be automatically mounted at system startup, 158the 159.Va extra_netfs_types 160.Xr rc.conf 5 161variable must be used to extend the 162.Xr rc 8 163startup script's list of network file system types. 164.Pp 165The type of the mount is extracted from the 166.Fa fs_mntops 167field and stored separately in the 168.Fa fs_type 169field (it is not deleted from the 170.Fa fs_mntops 171field). 172If 173.Fa fs_type 174is ``rw'' or ``ro'' then the file system whose name is given in the 175.Fa fs_file 176field is normally mounted read-write or read-only on the 177specified special file. 178If 179.Fa fs_type 180is ``sw'' then the special file is made available as a piece of swap 181space by the 182.Xr swapon 8 183command at the end of the system reboot procedure. 184The fields other than 185.Fa fs_spec 186and 187.Fa fs_type 188are unused. 189If 190.Fa fs_type 191is specified as ``xx'' the entry is ignored. 192This is useful to show disk partitions which are currently unused. 193.Pp 194The fifth field, 195.Pq Fa fs_freq , 196is used for these file systems by the 197.Xr dump 8 198command to determine which file systems need to be dumped. 199If the fifth field is not present, a value of zero is returned and 200.Nm dump 201will assume that the file system does not need to be dumped. 202.Pp 203The sixth field, 204.Pq Fa fs_passno , 205is used by the 206.Xr fsck 8 207and 208.Xr quotacheck 8 209programs to determine the order in which file system and quota 210checks are done at reboot time. 211The 212.Fa fs_passno 213field can be any value between 0 and 214.Ql INT_MAX Ns -1 . 215.Pp 216The root file system should be specified with a 217.Fa fs_passno 218of 1, and other file systems should have a 219.Fa fs_passno 220of 2 or greater. 221A file system with a 222.Fa fs_passno 223value of 1 is always checked sequentially and be completed before 224another file system is processed, and it will be processed before 225all file systems with a larger 226.Fa fs_passno . 227.Pp 228For any given value of 229.Fa fs_passno , 230file systems within a drive will be checked sequentially, 231but file systems on different drives will be checked at the 232same time to utilize parallelism available in the hardware. 233Once all file system checks are complete for the current 234.Fa fs_passno , 235the same process will start over for the next 236.Fa fs_passno . 237.Pp 238If the sixth field is not present or is zero, 239a value of zero is returned and 240.Xr fsck 8 241and 242.Xr quotacheck 8 243will assume that the file system does not need to be checked. 244.Pp 245The 246.Fa fs_passno 247field can be used to implement finer control when 248the system utilities may determine that the file system resides 249on a different physical device, when it actually does not, as with a 250.Xr ccd 4 251device. 252All file systems with a lower 253.Fa fs_passno 254value will be completed before starting on file systems with a 255higher 256.Fa fs_passno 257value. 258E.g. all file systems with a 259.Fa fs_passno 260of 2 will be completed before any file systems with a 261.Fa fs_passno 262of 3 or greater are started. 263Gaps are allowed between the different 264.Fa fs_passno 265values. 266E.g. file systems listed in 267.Pa /etc/fstab 268may have 269.Fa fs_passno 270values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order 271within 272.Pa /etc/fstab . 273.Bd -literal 274#define FSTAB_RW "rw" /* read/write device */ 275#define FSTAB_RQ "rq" /* read/write with quotas */ 276#define FSTAB_RO "ro" /* read-only device */ 277#define FSTAB_SW "sw" /* swap device */ 278#define FSTAB_XX "xx" /* ignore totally */ 279 280struct fstab { 281 char *fs_spec; /* block special device name */ 282 char *fs_file; /* file system path prefix */ 283 char *fs_vfstype; /* File system type, ufs, nfs */ 284 char *fs_mntops; /* Mount options ala -o */ 285 char *fs_type; /* FSTAB_* from fs_mntops */ 286 int fs_freq; /* dump frequency, in days */ 287 int fs_passno; /* pass number on parallel fsck */ 288}; 289.Ed 290.Pp 291The proper way to read records from 292.Pa fstab 293is to use the routines 294.Xr getfsent 3 , 295.Xr getfsspec 3 , 296.Xr getfstype 3 , 297and 298.Xr getfsfile 3 . 299.Sh FILES 300.Bl -tag -width /etc/fstab -compact 301.It Pa /etc/fstab 302The file 303.Nm 304resides in 305.Pa /etc . 306.El 307.Sh SEE ALSO 308.Xr getfsent 3 , 309.Xr getvfsbyname 3 , 310.Xr ccd 4 , 311.Xr dump 8 , 312.Xr fsck 8 , 313.Xr mount 8 , 314.Xr quotacheck 8 , 315.Xr quotaon 8 , 316.Xr swapon 8 , 317.Xr umount 8 318.Sh HISTORY 319The 320.Nm 321file format appeared in 322.Bx 4.0 . 323