FSTAB(5)							   File Formats 							  FSTAB(5)

NAME

       fstab - static information about the filesystems

SYNOPSIS

       /etc/fstab

DESCRIPTION

       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.  Lines starting with '#' are comments, blank lines are ignored. 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).
	      This field describes the block special device or remote filesystem to be mounted.

	      For ordinary mounts it will hold (a link to) a block special device node (as created by mknod(8)) for the device to be mounted, like
	      `/dev/cdrom' or `/dev/sdb7'.  For NFS mounts one will have <host>:<dir>, e.g., `knuth.aeb.nl:/'.	For procfs, use `proc'.

	      Instead of giving the device explicitly, one may indicate the filesystem that is to be mounted by its UUID or LABEL (cf.	e2label(8)
	      or xfs_admin(8)), writing LABEL=<label> or UUID=<uuid>, e.g., `LABEL=Boot' or `UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'.

	      It's also possible to use PARTUUID= and PARTLABEL=. These partitions identifiers are supported for GUID Partition  Table	(GPT)  and
	      MAC partition table only.

	      See blkid(8) or lsblk(8) for more details about devices identifiers.

	      Note that mount(8) uses UUIDs as strings. The string representation of the UUID should be based on lower case characters.

       The second field (fs_file).
	      This field describes the mount point for the filesystem.	For swap partitions, this field should be specified as `none'. If the name
	      of the mount point contains spaces these can be escaped as `40'.

       The third field (fs_vfstype).
	      This field describes the type of the filesystem.	Linux supports lots of filesystem types, such as adfs, affs, autofs, coda,  coher-
	      ent,  cramfs,  devpts, efs, ext2, ext3, hfs, hpfs, iso9660, jfs, minix, msdos, ncpfs, nfs, ntfs, proc, qnx4, reiserfs, romfs, smbfs,
	      sysv, tmpfs, udf, ufs, umsdos, vfat, xenix, xfs, and possibly others. For more details, see mount(8).

	      For the filesystems currently supported by the running kernel, see /proc/filesystems.

	      An entry swap denotes a file or partition to be used for swapping, cf. swapon(8).  An entry none is useful for bind or move mounts.

	      mount(8) and umount(8) support filesystem subtypes.  The subtype is defined by '.subtype' suffix.  For  example  'fuse.sshfs'.  It's
	      recommended  to  use subtype notation rather than add any prefix to the first fstab field (for example 'sshfs#example.com' is depre-
	      cated).

       The fourth field (fs_mntops).
	      This field 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  appropri-
	      ate to the filesystem type. For documentation on the available mount options, see mount(8).  For documentation on the available swap
	      options, see swapon(8).

	      Basic file system independent options are:

	      defaults
		     use default options: rw, suid, dev, exec, auto, nouser, and async.

	      noauto do not mount when "mount -a" is given (e.g., at boot time)

	      user   allow a user to mount

	      owner  allow device owner to mount

	      comment
		     or x-<name> for use by fstab-maintaining programs

	      nofail do not report errors for this device if it does not exist.

       The fifth field (fs_freq).
	      This field 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).
	      This  field  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.

NOTES

       The proper way to read records from fstab is to use the routines getmntent(3) or libmount.

       The keyword ignore as filesystem type (3rd field) is not more supported by the pure libmount based mount utility (since util-linux v2.22).

FILES

       /etc/fstab, <fstab.h>

SEE ALSO

       findmnt(8), mount(8), swapon(8), fs(5), getmntent(3)

HISTORY

       The ancestor of this fstab file format appeared in 4.0BSD.

AVAILABILITY

       This man page is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

util-linux							    August 2010 							  FSTAB(5)