mke2fs - create a Linux second extended file system


SYNOPSIS

       mke2fs  [  -c | -l filename ] [ -b block-size ] [ -f frag­
       ment-size ] [ -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 ] [ -R raid-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


DESCRIPTION

       mke2fs is used to create a Linux second extended file sys­
       tem on a device (usually 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.


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 determined by  the
              file  system  size  and  the  expected usage of the
              filesystem (see the -T option).

       -c     Check the device for bad blocks before creating the
              file system, using a fast read-only test.

       -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.

       -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  gen­
              erally  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  cre­
              ated,  so be careful deciding the correct value for
              this parameter.

              -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 sepa­
              rated, and may take an argument  using  the  equals
              ('=')   sign.   The  following  journal options are
              supported:

                   size=journal-size
                          Create a journal stored in the filesys­
                          tem  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.  The journal
                          must   fit  within  the  newly  created
                          filesystem.

                   device=external-journal
                          Attach the filesystem  to  the  journal
                          block  device located on external-jour­
                          nal.  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.

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

       -l filename
              Read the bad blocks list from filename.

       -L     Set the volume label for the filesystem.

       -m reserved-blocks-percentage
              Specify the percentage  of  the  filesystem  blocks
              reserved  for  the super-user.  This value defaults
              to 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


       -n     causes  mke2fs to not actually create a filesystem,
              but display what it would do if it were to create a
              filesystem.

       -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).  Currently, the sparse_super and filetype
              features are turned on by default unless mke2fs  is
              run  on  a  system  with  a  pre-2.2  Linux kernel.
              Filesystems that may need  to  mounted  on  pre-2.2
              kernels should be created with -O none (or -r 0 for
              1.2 kernels) which  will  disable  these  features,
              even if mke2fs is run on a system which can support
              them.

              The following filesystem options are supported:

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

                   filetype
                          Store file type information  in  direc­
                          tory 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.

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


       -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.

       -R raid-options
              Set  raid-related options for the filesystem.  Raid
              options are comma separated, and may take an  argu­
              ment  using  the  equals ('=') sign.  The following
              options are supported:

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

       -S     Write superblock and group descriptors only.   This
              is  useful  if  all  of  the  superblock and backup
              superblocks are corrupted, and a last-ditch  recov­
              ery  method is desired.  It causes mke2fs to reini­
              tialize 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 salvageable.  It
              is  critical  to  specify  the  correct  filesystem
              blocksize 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 chose optimal filesystem parameters
              for that use.  The supported filesystem types are:

                   news        one inode per 4kb block

                   largefile   one inode per megabyte

                   largefile4  one inode per 4 megabytes

       -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  second extended file system does not support

       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

       badblocks(8), dumpe2fs(8), e2fsck(8), tune2fs(8)


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