fstab - static information about the filesystems


#include <fstab.h>


The file fstab 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. The order of records in fstab is important because fsck (8), mount (8), and umount (8) sequentially iterate through fstab doing their thing.
The first field, ( fs_spec ), describes the block special device or remote filesystem to be mounted.
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 three types of filesystems:

a local filesystem, supporting filenames of length 14 or 30 characters.

a local filesystem with longer filenames and larger inodes. This filesystem has been replaced by the ext2 file system, and should no longer be used.

a local filesystem with longer filenames, larger inodes, and lots of other features.

a local filesystem with longer filenames, larger inodes, and lots of other features.

a local filesystem for MS-DOS partitions.

a local filesystem for HPFS partitions.

a local filesystem used for CD-ROM drives.

a filesystem for mounting partitions from remote systems.

a disk partition to be used for swapping.

If vfs_fstype is specified as ``ignore'' the entry is ignored. This is useful to show disk partitions which are currently unused.
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 plus any additional options appropriate to the filesystem type. For documentation on the available options for non-nfs file systems, see mount (8). For documentation on all nfs-specific options have a look at nfs (5).
The fifth field, ( fs_freq ), is used for these filesystems by the dump (8) command to determine which filesystems need to be dumped. If the fifth field is not present, a value of zero is returned and dump 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 zero, a value of zero is returned and fsck will assume that the filesystem does not need to be checked.
The proper way to read records from fstab is to use the routines getmntent (3).


/etc/fstab The file fstab resides in /etc .


The documentation in mount (8) is often more up-to-date.


getmntent (3), mount (8), swapon (8), nfs (5)


The fstab file format appeared in 4.0BSD.