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MKE2FS(8)							     MKE2FS(8)



NAME
       mke2fs - create an ext2/ext3 filesystem

SYNOPSIS
       mke2fs [ -c | -l filename ] [ -b block-size ] [ -f fragment-size ] [ -g
       blocks-per-group ] [ -i bytes-per-inode ] [ -j ] [ -J journal-options ]
       [  -N  number-of-inodes ] [ -n ] [ -m reserved-blocks-percentage ] [ -o
       creator-os ] [ -O feature[,...]	] [ -q ] [ -r fs-revision-level ] [ -E
       extended-options ] [ -v ] [ -F ] [ -L volume-label ] [ -M last-mounted-
       directory ] [ -S ] [ -T filesystem-type ] [ -V ] device [  blocks-count
       ]

       mke2fs -O journal_dev [ -b block-size ] [ -L volume-label ] [ -n ] [ -q
       ] [ -v ] external-journal [ blocks-count ]

DESCRIPTION
       mke2fs is used to create an ext2/ext3 filesystem	 (usually  in  a  disk
       partition).   device  is	 the  special file corresponding to the device
       (e.g /dev/hdXX).	 blocks-count is the number of blocks on  the  device.
       If  omitted,  mke2fs  automagically  figures  the file system size.  If
       called as mkfs.ext3 a journal is created as if the -j option was speci-
       fied.

OPTIONS
       -b block-size
	      Specify the size of blocks in bytes.  Valid block size vales are
	      1024, 2048 and 4096 bytes per block.  If omitted, mke2fs	block-
	      size is heuristically determined by the file system size and the
	      expected usage of the filesystem (see the -T option).  If block-
	      size  is	negative, then mke2fs will use heuristics to determine
	      the appropriate block size, with the constraint that  the	 block
	      size will be at least block-size bytes.  This is useful for cer-
	      tain hardware devices which require that the blocksize be a mul-
	      tiple of 2k.

       -c     Check the device for bad blocks before creating the file system.
	      If this option is specified twice,  then	a  slower,  read-write
	      test is used instead of a fast read-only test.

       -E extended-options
	      Set  extended  options for the filesystem.  Extended options are
	      comma separated, and may take an argument using the equals ('=')
	      sign.   The  -E  option  used  to	 be  -R in earlier versions of
	      mke2fs.  The -R option is still accepted for backwards  compati-
	      bility.	The following extended options are supported:

		   stride=stripe-size
			  Configure  the  filesystem  for  a  RAID  array with
			  stripe-size filesystem blocks per stripe.

		   resize=max-online-resize
			  Reserve  enough  space  so  that  the	 block	 group
			  descriptor  table  can  grow to support a filesystem
			  that has max-online-resize blocks.

       -f fragment-size
	      Specify the size of fragments in bytes.

       -F     Force mke2fs to run, even if the specified device is not a block
	      special device, or appears to be mounted.

       -g blocks-per-group
	      Specify  the number of blocks in a block group.  There is gener-
	      ally no reason the user to  ever	set  this  parameter,  as  the
	      default  is optimal for the filesystem.  (For administrators who
	      are creating filesystems on RAID arrays, it is preferable to use
	      the  stride  RAID parameter as part of the -R option rather than
	      manipulating the number of blocks per group.)   This  option  is
	      generally used by developers who are developing test cases.

       -i bytes-per-inode
	      Specify  the  bytes/inode	 ratio.	  mke2fs  creates an inode for
	      every bytes-per-inode bytes of space on the  disk.   The	larger
	      the  bytes-per-inode  ratio,  the	 fewer inodes will be created.
	      This value generally shouldn't be smaller than the blocksize  of
	      the  filesystem,	since  then  too many inodes will be made.  Be
	      warned that is not possible to expand the number of inodes on  a
	      filesystem  after it is created, so be careful deciding the cor-
	      rect value for this parameter.

       -j     Create the filesystem with an ext3 journal.  If the -J option is
	      not  specified,  the  default journal parameters will be used to
	      create an appropriately sized journal (given  the	 size  of  the
	      filesystem) stored within the filesystem.	 Note that you must be
	      using a kernel which has ext3 support in order to actually  make
	      use of the journal.

       -J journal-options
	      Create  the ext3 journal using options specified on the command-
	      line.  Journal options are comma	separated,  and	 may  take  an
	      argument	using  the  equals ('=')  sign.	 The following journal
	      options are supported:

		   size=journal-size
			  Create an internal journal (i.e., stored inside  the
			  filesystem)  of  size	 journal-size  megabytes.  The
			  size of the journal must be at least 1024 filesystem
			  blocks  (i.e.,  1MB if using 1k blocks, 4MB if using
			  4k blocks, etc.)  and may be no  more	 than  102,400
			  filesystem blocks.

		   device=external-journal
			  Attach  the  filesystem  to the journal block device
			  located on external-journal.	The  external  journal
			  must already have been created using the command

			  mke2fs -O journal_dev external-journal

			  Note	that  external-journal	must have been created
			  with the same block size as the new filesystem.   In
			  addition,  while there is support for attaching mul-
			  tiple filesystems to a single external journal,  the
			  Linux	 kernel and e2fsck(8) do not currently support
			  shared external journals yet.

			  Instead of specifying a device name directly, exter-
			  nal-journal	can   also   be	 specified  by	either
			  LABEL=label or  UUID=UUID  to	 locate	 the  external
			  journal by either the volume label or UUID stored in
			  the ext2 superblock at the  start  of	 the  journal.
			  Use dumpe2fs(8) to display a journal device's volume
			  label	 and  UUID.   See  also	 the  -L   option   of
			  tune2fs(8).

	      Only  one	 of  the  size	or  device  options can be given for a
	      filesystem.

       -l filename
	      Read the bad blocks list from filename.	Note  that  the	 block
	      numbers  in  the bad block list must be generated using the same
	      block size as used by mke2fs.  As a result,  the	-c  option  to
	      mke2fs is a much simpler and less error-prone method of checking
	      a disk for bad blocks before formatting it, as mke2fs will auto-
	      matically	 pass the correct parameters to the badblocks program.

       -L new-volume-label
	      Set the volume label for	the  filesystem	 to  new-volume-label.
	      The maximum length of the volume label is 16 bytes.

       -m reserved-blocks-percentage
	      Specify the percentage of the filesystem blocks reserved for the
	      super-user.  This avoids fragmentation,  and  allows  root-owned
	      daemons,	such  as syslogd(8), to continue to function correctly
	      after non-privileged processes are prevented from writing to the
	      filesystem.  The default percentage is 5%.

       -M     Set  the	last mounted directory for the filesystem.  This might
	      be useful for the sake of utilities that key  off	 of  the  last
	      mounted  directory  to  determine where the filesystem should be
	      mounted.

       -n     causes mke2fs to not actually create a filesystem,  but  display
	      what it would do if it were to create a filesystem.  This can be
	      used to determine the location of the backup superblocks	for  a
	      particular  filesystem,  so  long	 as the mke2fs parameters that
	      were passed when the filesystem was originally created are  used
	      again.  (With the -n option added, of course!)

       -N number-of-inodes
	      overrides	 the  default calculation of the number of inodes that
	      should be reserved for the filesystem (which  is	based  on  the
	      number  of  blocks  and the bytes-per-inode ratio).  This allows
	      the user to specify the number of desired inodes directly.

       -o creator-os
	      Manually override the default value of the "creator os" field of
	      the filesystem.  Normally the creator field is set by default to
	      the native OS of the mke2fs executable.

       -O feature[,...]
	      Create filesystem	 with  given  features	(filesystem  options),
	      overriding the default filesystem options.  The default features
	      which are enabled by default are specified by the	 base_features
	      relation,	  either   in	the   [libdefaults]   section  in  the
	      /etc/mke2fs.conf configuration file, or in the subsection of the
	      [fs_types]  section  for the filesystem type as specified by the
	      -T option.  The filesystem type-specific	configuration  setting
	      found in the [fs_types] section will override the global default
	      found in [libdefaults].

	      The filesystem feature set will be further edited	 using	either
	      the  feature  set	 specification specified by this option, or if
	      this option is not specified, by the  default_features  relation
	      for  the	filesystem type being created, or in the [libdefaults]
	      section of the configuration file.

	      The filesystem feature set is comprised of a list	 of  features,
	      separated	 by commas, that are to be enabled.  To disable a fea-
	      ture, simply prefix the feature name with a  caret ('^') charac-
	      ter.   The  pseudo-filesystem  feature  "none"  will  clear  all
	      filesystem features.

		   dir_index
			  Use hashed b-trees to	 speed	up  lookups  in	 large
			  directories.

		   filetype
			  Store file type information in directory entries.

		   has_journal
			  Create  an ext3 journal (as if using the -j option).

		   journal_dev
			  Create an external ext3 journal on the given	device
			  instead  of  a  regular  ext2 filesystem.  Note that
			  external-journal must be created with the same block
			  size as the filesystems that will be using it.

		   resize_inode
			  Reserve  space  so  the block group descriptor table
			  may grow in the future.  Useful for online  resizing
			  using	 resize2fs.  By default mke2fs will attempt to
			  reserve enough space so that the filesystem may grow
			  to 1024 times its initial size.  This can be changed
			  using resize extended option.

		   sparse_super
			  Create a filesystem  with  fewer  superblock	backup
			  copies (saves space on large filesystems).

       -q     Quiet execution.	Useful if mke2fs is run in a script.

       -r revision
	      Set  the	filesystem revision for the new filesystem.  Note that
	      1.2 kernels only support revision 0 filesystems.	The default is
	      to create revision 1 filesystems.

       -S     Write  superblock and group descriptors only.  This is useful if
	      all of the superblock and backup superblocks are corrupted,  and
	      a	 last-ditch  recovery  method is desired.  It causes mke2fs to
	      reinitialize the superblock and  group  descriptors,  while  not
	      touching	the  inode table and the block and inode bitmaps.  The
	      e2fsck program should be run immediately after  this  option  is
	      used,  and  there is no guarantee that any data will be salvage-
	      able.  It is critical to specify the correct  filesystem	block-
	      size  when using this option, or there is no chance of recovery.

       -T fs-type
	      Specify how the filesystem is going to be used, so  that	mke2fs
	      can  choose  optimal  filesystem	parameters  for that use.  The
	      filesystem types that are can be supported are  defined  in  the
	      configuration  file /etc/mke2fs.conf(5).	The default configura-
	      tion file contains definitions for the filesystem types:	small,
	      floppy, news, largefile, and largefile4.

       -v     Verbose execution.

       -V     Print the version number of mke2fs and exit.

AUTHOR
       This   version	of   mke2fs   has   been   written  by	Theodore  Ts'o
       <tytso@mit.edu>.

BUGS
       mke2fs accepts the -f option but currently ignores it because the  sec-
       ond extended file system does not support fragments yet.
       There may be other ones.	 Please, report them to the author.

AVAILABILITY
       mke2fs  is  part	 of  the  e2fsprogs  package  and  is  available  from
       http://e2fsprogs.sourceforge.net.

SEE ALSO
       mke2fs.conf(5), badblocks(8), dumpe2fs(8), e2fsck(8), tune2fs(8)



E2fsprogs version 1.39		   May 2006			     MKE2FS(8)
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