FSTAB(5) OpenBSD Programmer's Manual FSTAB(5)NAMEfstab - static information about the filesystems
SYNOPSIS
#include <fstab.h>
DESCRIPTION
The fstab file contains descriptive information about the various file
systems. fstab is only read by programs, and not written; it is the duty
of the system administrator to properly create and maintain this file.
Each filesystem is described on a separate line; fields on each line are
separated by tabs or spaces. Lines beginning with the `#' character are
comments and are ignored. The order of records in fstab is important
because fsck(8) and mount(8) sequentially iterate through fstab doing
their thing.
A line has the following format:
fs_spec fs_file fs_vfstype fs_mntops fs_freq fs_passno
The first field, fs_spec, describes the block special device or remote
filesystem to be mounted. A block special device may be specified by
pathname or by disklabel(8) UID (DUID). For filesystems of type MFS the
special file name is typically that of the primary swap area; if the
keyword ``swap'' is used instead of a special file name, default
configuration parameters are used. If a program needs the character
special file name, the program must create it by appending an `r' after
the last `/' in the special file name.
The second field, fs_file, describes the mount point for the filesystem.
For swap partitions, this field should be specified as ``none''.
The third field, fs_vfstype, describes the type of the filesystem. The
system currently supports the following types of filesystems:
cd9660 An ISO 9660 CD-ROM filesystem.
ext2fs A local Linux compatible ext2fs filesystem.
ffs A local UNIX filesystem.
mfs A local memory-based UNIX filesystem.
msdos An MS-DOS FAT filesystem.
nfs A Sun Microsystems compatible Network File System.
ntfs An NTFS filesystem.
procfs A local filesystem containing process information.
swap A disk partition to be used for swapping.
udf A UDF filesystem.
vnd A VND image file.
The fourth field, fs_mntops, describes the mount options associated with
the filesystem. It is formatted as a comma separated list of options.
It contains at least the type of mount (see fs_type below) plus any
additional options appropriate to the filesystem type.
The option ``auto'' can be used in the ``noauto'' form to cause a file
system not to be mounted automatically (with mount -A or mount -a, or at
system boot time).
If the options ``userquota'' and/or ``groupquota'' are specified, the
filesystem is automatically processed by the quotacheck(8) command, and
user and/or group disk quotas are enabled with quotaon(8). By default,
filesystem quotas are maintained in files named quota.user and
quota.group which are located at the root of the associated filesystem.
These defaults may be overridden by putting an equal sign and an
alternative absolute pathname following the quota option. Thus, if the
user quota file for /tmp is stored in /var/quotas/tmp.user, this location
can be specified as:
userquota=/var/quotas/tmp.user
The type of the mount is extracted from the first parameter of the
fs_mntops field and stored separately in the fs_type field (it is not
deleted from the fs_mntops field). If fs_type is ``rw'', ``rq'', or
``ro'' then the filesystem whose name is given in the fs_file field is
normally mounted read-write or read-only on the specified special file.
If fs_type is ``sw'' then the special file is made available as a piece
of swap space by the swapon(8) command at the end of the system reboot
procedure. The fields other than fs_spec and fs_type are unused. If
fs_type is specified as ``xx'' the entry is ignored. This is useful to
show disk partitions which are currently unused.
The fifth field, fs_freq, is used by the -W and -w options of dump(8) to
recommend which filesystems should be backed up. The value specifies the
number of days after which a dump is regarded as being old; if it is not
present, a value of zero is returned and dump(8) will assume that the
filesystem does not need to be dumped.
The sixth field, fs_passno, is used by the fsck(8) program to determine
the order in which filesystem checks are done at reboot time. The root
filesystem should be specified with a fs_passno of 1, and other
filesystems should have a fs_passno of 2. Filesystems within a drive
will be checked sequentially, but filesystems on different drives will be
checked at the same time to utilize parallelism available in the
hardware. If the sixth field is not present or is zero, a value of zero
is returned and fsck(8) will assume that the filesystem does not need to
be checked.
#define FSTAB_RW "rw" /* read/write device */
#define FSTAB_RQ "rq" /* read/write with quotas *
#define FSTAB_RO "ro" /* read-only device */
#define FSTAB_SW "sw" /* swap device */
#define FSTAB_XX "xx" /* ignore totally */
struct fstab {
char *fs_spec; /* block special device name */
char *fs_file; /* filesystem path prefix */
char *fs_vfstype; /* type of filesystem */
char *fs_mntops; /* comma separated mount options */
char *fs_type; /* rw, rq, ro, sw, or xx */
int fs_freq; /* dump frequency, in days */
int fs_passno; /* pass number on parallel fsck */
};
The proper way to read records from fstab is to use the routines
getfsent(3), getfsspec(3), and getfsfile(3).
FILES
/etc/fstab
EXAMPLES
Here is a sample /etc/fstab file:
/dev/sd0a / ffs rw 1 1
/dev/sd0e /var ffs rw,nodev,nosuid 1 2
#/dev/sd0f /tmp ffs rw,nodev,nosuid 1 2
swap /tmp mfs rw,nodev,nosuid,-s=153600 0 0
/dev/sd0g /usr ffs rw,nodev 1 2
/dev/sd0h /usr/local ffs rw,nodev 1 2
/dev/sd0i /home ffs rw,nodev,nosuid 1 2
/dev/sd0j /usr/src ffs rw,nodev,nosuid,softdep 1 2
/dev/sd1b none swap sw 0 0
/dev/cd0a /cdrom cd9660 ro,noauto 0 0
5b27c2761a9b0b06.i /mnt/key msdos rw,noauto 0 0
server:/export/ports /usr/ports nfs rw,nodev,nosuid,soft,intr 0 0
SEE ALSOquota(1), getfsent(3), fsck(8), mount(8), quotacheck(8), quotaon(8)HISTORY
The fstab file format appeared in 4.0BSD.
OpenBSD 4.9 September 28, 2010 OpenBSD 4.9
