FSTAB(5)                            Linux Programmer's Manual                            FSTAB(5)



NAME
       fstab - static information about the filesystems

SYNOPSIS
       #include <fstab.h>

DESCRIPTION
       The file fstab contains descriptive information about the various file systems.  It is the
       duty of the system administrator to properly create and maintain this file.  fstab can  be
       modified  by special utils (e.g.  fstab-sync(8)).  Each filesystem is described on a sepa-
       rate line; fields on each line are separated by tabs or spaces.  Lines starting  with  '#'
       are  comments.   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.

       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 (ext2 or xfs) filesystem
       that is to be mounted by its UUID or volume label (cf.  e2label(8) or xfs_admin(8)), writ-
       ing  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 filesystem.  For swap par-
       titions, this field should be specified as 'none'. If the name of the mount point contains
       spaces these can be escaped as '\040'.

       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 ker-
       nel, 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), ''owner'' (allow  device  owner  to  mount),  and  ''pamconsole''
       (allow  a  user  at  the console to mount), and ''_netdev'' (device requires network to be
       available).  The ''owner'', ''pamconsole'' 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 deter-
       mine 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).

FILES
       /etc/fstab

SEE ALSO
       getmntent(3), mount(8), swapon(8), fs(5) nfs(5) fstab-sync(8)

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



Linux 2.2                                  15 June 1999                                  FSTAB(5)