fstab - static information about the filesystems




   The  file  fstab contains descriptive information about the filesystems
   the system can mount.  fstab is only read by programs, and not written;
   it  is  the  duty  of  the  system administrator to properly create and
   maintain this file.  The order of records in fstab is important because
   fsck(8),  mount(8),  and  umount(8)  sequentially iterate through fstab
   doing their thing.

   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 following is a typical example of an fstab entry:

          LABEL=t-home2   /home      ext4    defaults,auto_da_alloc      0

   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, this
          field  is <host>:<dir>, e.g., `knuth.aeb.nl:/'.  For filesystems
          with no storage, any string can be used, and  will  show  up  in
          df(1)  output, for example.  Typical usage is `proc' for procfs;
          `mem', `none', or `tmpfs' for tmpfs.  Other special filesystems,
          like udev and sysfs, are typically not listed in fstab.

          LABEL=<label>  or  UUID=<uuid>  may be given instead of a device
          name.  This is the recommended method, as device names are often
          a  coincidence  of hardware detection order, and can change when
          other disks are added or removed.  For example, `LABEL=Boot'  or
          `UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'.  (Use a filesystem-
          specific tool like e2label(8), xfs_admin(8), or  fatlabel(8)  to
          set LABELs on filesystems).

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

          See mount(8), blkid(8) or lsblk(8) for more details about device

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

   The second field (fs_file).
          This  field  describes  the  mount  point   (target)   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 `\040'.

   The third field (fs_vfstype).
          This field describes the type of the filesystem.  Linux supports
          many filesystem types:  ext4,  xfs,  btrfs,  f2fs,  vfat,  ntfs,
          hfsplus,  tmpfs, sysfs, proc, iso9660, udf, squashfs, nfs, cifs,
          and many more.  For more details, see mount(8).

          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.

          More than one type may be specified in a comma-separated list.

          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

   The fourth field (fs_mntops).
          This field describes  the  mount  options  associated  with  the

          It  is  formatted  as  a  comma-separated  list  of options.  It
          contains at least the  type  of  mount  (ro  or  rw),  plus  any
          additional options appropriate to the filesystem type (including
          performance-tuning  options).   For  details,  see  mount(8)  or

          Basic filesystem-independent options are:

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

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

          user   allow a user to mount

          owner  allow device owner to mount

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

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

   The fifth field (fs_freq).
          This field is used by dump(8)  to  determine  which  filesystems
          need  to  be  dumped.   Defaults  to  zero  (don't  dump) if not

   The sixth field (fs_passno).
          This field is used by fsck(8) to determine the  order  in  which
          filesystem  checks  are  done at boot time.  The root filesystem
          should be specified with a fs_passno of  1.   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.  Defaults to zero (don't fsck) if not


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

   The keyword ignore as a  filesystem  type  (3rd  field)  is  no  longer
   supported  by  the  pure libmount based mount utility (since util-linux


   /etc/fstab, <fstab.h>


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


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


   This man page is part of the util-linux package and is  available  from


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