fstab

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.  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
       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)),  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
       `\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 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
       device  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-
       tent(3).

FILES
       /etc/fstab

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

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



Linux 2.2                        15 June 1999                         FSTAB(5)