fstab


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, though at boot time mountall(8) may  process  the  file  out-of-
       order when it believes it is safe to do so.

       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.  An entry  none  is  useful
       for bind or move mounts.

       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
       remote filesystems to explicitly instruct mountall(8) not  to  hold  up
       the boot for them; ``optional'' which causes the entry to be ignored if
       the filesystem type is not known  at  boot  time;  and  ``showthrough''
       which  permits  a mountpoint to be mounted before its parent mountpoint
       (this latter should be used carefully, as it can cause boot hangs).

       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), mountall(8), swapon(8), fs(5), nfs(5)

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

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



Linux 2.2                        15 June 1999                         FSTAB(5)
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