Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
FSTAB(5)		   Linux Programmer's Manual		      FSTAB(5)

       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.  Lines starting with '#' are com-
       ments.  The order of records in fstab  is  important  because  fsck(8),
       mount(8),  and umount(8)	sequentially iterate through fstab doing their

       The first field,	(fs_spec), describes the block special device  or  re-
       mote 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., `'.  For procfs, use `proc'.

       Instead of giving the device explicitly,	one may	indicate the (ext2  or
       xfs)  filesystem	that is	to be mounted by its UUID or volume 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'.
       This will make the system more robust: adding or	removing a  SCSI  disk
       changes the disk	device name but	not the	filesystem volume label.

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

       The third field,	(fs_vfstype), describes	the type  of  the  filesystem.
       Linux  supports	lots  of filesystem types, such	as adfs, affs, autofs,
       coda, coherent, 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 ignore causes the line to be 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).  Common for all types of file system are
       the options ``noauto'' (do not mount when "mount	-a" is given, e.g., at
       boot time), ``user'' (allow a user to mount), and ``owner'' (allow  de-
       vice  owner  to	mount),	and ``_netdev''	(device	requires network to be
       available).  The	``owner'' and ``_netdev'' options are  Linux-specific.
       For more	details, see mount(8).

       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	deter-
       mine 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	getmn-


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

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

Linux 2.2			 15 June 1999			      FSTAB(5)


Want to link to this manual page? Use this URL:

home | help