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. 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.\" $FreeBSD$ 30.\" 31.Dd April 14, 2014 32.Dt FSTAB 5 33.Os 34.Sh NAME 35.Nm fstab 36.Nd static information about the file systems 37.Sh SYNOPSIS 38.In fstab.h 39.Sh DESCRIPTION 40The file 41.Nm 42contains descriptive information about the various file 43systems. 44.Nm 45is only read by programs, and not written; 46it is the duty of the system administrator to properly create 47and maintain this file. 48Each file system is described on a separate line; 49fields on each line are separated by tabs or spaces. 50The order of records in 51.Nm 52is important because 53.Xr fsck 8 , 54.Xr mount 8 , 55and 56.Xr umount 8 57sequentially iterate through 58.Nm 59doing their thing. 60.Pp 61The first field, 62.Pq Fa fs_spec , 63describes the special device or 64remote file system to be mounted. 65The contents are decoded by the 66.Xr strunvis 3 67function. 68This allows using spaces or tabs in the device name which would be 69interpreted as field separators otherwise. 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 . 76The contents are decoded by the 77.Xr strunvis 3 78function, as above. 79.Pp 80The third field, 81.Pq Fa fs_vfstype , 82describes the type of the file system. 83The system can support various file system types. 84Only the root, /usr, and /tmp file systems need be statically 85compiled into the kernel; 86everything else will be automatically loaded at mount 87time. 88(Exception: the FFS cannot currently be demand-loaded.) 89Some people still prefer to statically 90compile other file systems as well. 91.Pp 92The fourth field, 93.Pq Fa fs_mntops , 94describes the mount options associated with the file system. 95It is formatted as a comma separated list of options. 96It contains at least the type of mount (see 97.Fa fs_type 98below) plus any additional options appropriate to the file system type. 99See the options flag 100.Pq Fl o 101in the 102.Xr mount 8 103page and the file system specific page, such as 104.Xr mount_nfs 8 , 105for additional options that may be specified. 106All options that can be given to the file system specific mount commands 107can be used in 108.Nm 109as well. 110They just need to be formatted a bit differently. 111The arguments of the 112.Fl o 113option can be used without the preceding 114.Fl o 115flag. 116Other options need both the file system specific flag and its argument, 117separated by an equal sign. 118For example, mounting an 119.Xr msdosfs 5 120filesystem, the options 121.Bd -literal -offset indent 122-o sync -o noatime -m 644 -M 755 -u foo -g bar 123.Ed 124.Pp 125should be written as 126.Bd -literal -offset indent 127sync,noatime,-m=644,-M=755,-u=foo,-g=bar 128.Ed 129.Pp 130in the option field of 131.Nm . 132.Pp 133If the options 134.Dq userquota 135and/or 136.Dq groupquota 137are specified, 138the file system is automatically processed by the 139.Xr quotacheck 8 140command, and user and/or group disk quotas are enabled with 141.Xr quotaon 8 . 142By default, 143file system quotas are maintained in files named 144.Pa quota.user 145and 146.Pa quota.group 147which are located at the root of the associated file system. 148These defaults may be overridden by putting an equal sign 149and an alternative absolute pathname following the quota option. 150Thus, if the user quota file for 151.Pa /tmp 152is stored in 153.Pa /var/quotas/tmp.user , 154this location can be specified as: 155.Bd -literal -offset indent 156userquota=/var/quotas/tmp.user 157.Ed 158.Pp 159If the option 160.Dq failok 161is specified, 162the system will ignore any error which happens during the mount of that filesystem, 163which would otherwise cause the system to drop into single user mode. 164This option is implemented by the 165.Xr mount 8 166command and will not be passed to the kernel. 167.Pp 168If the option 169.Dq noauto 170is specified, the file system will not be automatically 171mounted at system startup. 172Note that, for network file systems 173of third party types 174(i.e., types supported by additional software 175not included in the base system) 176to be automatically mounted at system startup, 177the 178.Va extra_netfs_types 179.Xr rc.conf 5 180variable must be used to extend the 181.Xr rc 8 182startup script's list of network file system types. 183.Pp 184If the option 185.Dq late 186is specified, the file system will be automatically mounted 187at a stage of system startup after remote mount points are mounted. 188For more detail about this option, 189see the 190.Xr mount 8 191manual page. 192.Pp 193The type of the mount is extracted from the 194.Fa fs_mntops 195field and stored separately in the 196.Fa fs_type 197field (it is not deleted from the 198.Fa fs_mntops 199field). 200If 201.Fa fs_type 202is 203.Dq rw 204or 205.Dq ro 206then the file system whose name is given in the 207.Fa fs_file 208field is normally mounted read-write or read-only on the 209specified special file. 210.Pp 211If 212.Fa fs_type 213is 214.Dq sw 215then the special file is made available as a piece of swap 216space by the 217.Xr swapon 8 218command at the end of the system reboot procedure. 219For vnode-backed swap spaces, 220.Dq file 221is supported in the 222.Fa fs_mntops 223field. 224When 225.Fa fs_spec 226is an 227.Xr md 4 228device file 229.Pq Do md Dc or Do md[0-9]* Dc 230and 231.Dq file 232is specified in 233.Fa fs_mntopts , 234an 235.Xr md 4 236device is created with the specified file used as backing store, 237and then the new device is used as swap space. 238Swap entries on 239.Pa .eli 240devices will cause automatic creation of encrypted devices. 241The 242.Dq ealgo , 243.Dq aalgo , 244.Dq keylen , 245and 246.Dq sectorsize 247options may be passed to control those 248.Xr geli 8 249parameters. 250The fields other than 251.Fa fs_spec 252and 253.Fa fs_type 254are unused. 255If 256.Fa fs_type 257is specified as 258.Dq xx 259the entry is ignored. 260This is useful to show disk partitions which are currently unused. 261.Pp 262The fifth field, 263.Pq Fa fs_freq , 264is used for these file systems by the 265.Xr dump 8 266command to determine which file systems need to be dumped. 267If the fifth field is not present, a value of zero is returned and 268.Nm dump 269will assume that the file system does not need to be dumped. 270If the fifth field is greater than 0, then it specifies the number of days 271between dumps for this file system. 272.Pp 273The sixth field, 274.Pq Fa fs_passno , 275is used by the 276.Xr fsck 8 277and 278.Xr quotacheck 8 279programs to determine the order in which file system and quota 280checks are done at reboot time. 281The 282.Fa fs_passno 283field can be any value between 0 and 284.Ql INT_MAX Ns -1 . 285.Pp 286The root file system should be specified with a 287.Fa fs_passno 288of 1, and other file systems should have a 289.Fa fs_passno 290of 2 or greater. 291A file system with a 292.Fa fs_passno 293value of 1 is always checked sequentially and be completed before 294another file system is processed, and it will be processed before 295all file systems with a larger 296.Fa fs_passno . 297.Pp 298For any given value of 299.Fa fs_passno , 300file systems within a drive will be checked sequentially, 301but file systems on different drives will be checked at the 302same time to utilize parallelism available in the hardware. 303Once all file system checks are complete for the current 304.Fa fs_passno , 305the same process will start over for the next 306.Fa fs_passno . 307.Pp 308If the sixth field is not present or is zero, 309a value of zero is returned and 310.Xr fsck 8 311and 312.Xr quotacheck 8 313will assume that the file system does not need to be checked. 314.Pp 315The 316.Fa fs_passno 317field can be used to implement finer control when 318the system utilities may determine that the file system resides 319on a different physical device, when it actually does not, as with a 320.Xr ccd 4 321device. 322All file systems with a lower 323.Fa fs_passno 324value will be completed before starting on file systems with a 325higher 326.Fa fs_passno 327value. 328E.g. all file systems with a 329.Fa fs_passno 330of 2 will be completed before any file systems with a 331.Fa fs_passno 332of 3 or greater are started. 333Gaps are allowed between the different 334.Fa fs_passno 335values. 336E.g. file systems listed in 337.Pa /etc/fstab 338may have 339.Fa fs_passno 340values such as 0, 1, 2, 15, 100, 200, 300, and may appear in any order 341within 342.Pa /etc/fstab . 343.Bd -literal 344#define FSTAB_RW "rw" /* read/write device */ 345#define FSTAB_RQ "rq" /* read/write with quotas */ 346#define FSTAB_RO "ro" /* read-only device */ 347#define FSTAB_SW "sw" /* swap device */ 348#define FSTAB_XX "xx" /* ignore totally */ 349 350struct fstab { 351 char *fs_spec; /* block special device name */ 352 char *fs_file; /* file system path prefix */ 353 char *fs_vfstype; /* File system type, ufs, nfs */ 354 char *fs_mntops; /* Mount options ala -o */ 355 char *fs_type; /* FSTAB_* from fs_mntops */ 356 int fs_freq; /* dump frequency, in days */ 357 int fs_passno; /* pass number on parallel fsck */ 358}; 359.Ed 360.Pp 361The proper way to read records from 362.Pa fstab 363is to use the routines 364.Xr getfsent 3 , 365.Xr getfsspec 3 , 366.Xr getfstype 3 , 367and 368.Xr getfsfile 3 . 369.Sh FILES 370.Bl -tag -width /etc/fstab -compact 371.It Pa /etc/fstab 372The file 373.Nm 374resides in 375.Pa /etc . 376.El 377.Sh EXAMPLES 378.Bd -literal 379# Device Mountpoint FStype Options Dump Pass# 380# 381# UFS file system. 382/dev/da0p2 / ufs rw 1 1 383# 384# Swap space on a block device. 385/dev/da0p1 none swap sw 0 0 386# 387# Swap space using a block device with GBDE/GELI encyption. 388# aalgo, ealgo, keylen, sectorsize options are available 389# for .eli devices. 390/dev/da1p1.bde none swap sw 0 0 391/dev/da1p2.eli none swap sw 0 0 392# 393# tmpfs. 394tmpfs /tmp tmpfs rw,size=1g,mode=1777 0 0 395# 396# UFS file system on a swap-backed md(4). /dev/md10 is 397# automatically created. If it is "md", a unit number 398# will be automatically selected. 399md10 /scratch mfs rw,-s1g 0 0 400# 401# Swap space on a vnode-backed md(4). 402md11 none swap sw,file=/swapfile 0 0 403# 404# CDROM. "noauto" option is typically used because the 405# media is removable. 406/dev/cd0 /cdrom cd9660 ro,noauto 0 0 407# 408# NFS-exported file system. "serv" is an NFS server name 409# or IP address. 410serv:/export /nfs nfs rw,noinet6 0 0 411.Ed 412.Sh SEE ALSO 413.Xr getfsent 3 , 414.Xr getvfsbyname 3 , 415.Xr strunvis 3 , 416.Xr ccd 4 , 417.Xr dump 8 , 418.Xr fsck 8 , 419.Xr geli 8 , 420.Xr mount 8 , 421.Xr quotacheck 8 , 422.Xr quotaon 8 , 423.Xr swapon 8 , 424.Xr umount 8 425.Sh HISTORY 426The 427.Nm 428file format appeared in 429.Bx 4.0 . 430