Provided by: e2fsprogs_1.42-1ubuntu2_i386 bug

NAME

       mke2fs - create an ext2/ext3/ext4 filesystem

SYNOPSIS

       mke2fs [ -c | -l filename ] [ -b block-size ] [ -f fragment-size ] [ -g
       blocks-per-group ] [ -G number-of-groups ] [ -i bytes-per-inode ] [  -I
       inode-size ] [ -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 fs-type ] [ -T usage-type ] [ -U UUID ] [ -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, or ext4 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
       specified.

       The defaults of the parameters for the newly created filesystem, if not
       overridden   by  the  options  listed  below,  are  controlled  by  the
       /etc/mke2fs.conf configuration file.   See  the  mke2fs.conf(5)  manual
       page for more details.

OPTIONS

       -b block-size
              Specify  the  size  of blocks in bytes.  Valid block-size values
              are 1024, 2048 and 4096 bytes per block.  If omitted, block-size
              is  heuristically  determined  by  the  filesystem  size and the
              expected usage of the filesystem (see the -T option).  If block-
              size  is preceded by a negative sign ('-'), 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  certain  hardware  devices  which
              require that the blocksize be a multiple 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
              compatibility.   The following extended options are supported:

                   mmp_update_interval=interval
                          Adjust  the  initial MMP update interval to interval
                          seconds.  Specifying an interval of 0 means  to  use
                          the  default  interval.  The specified interval must
                          be less than 300 seconds.   Requires  that  the  mmp
                          feature be enabled.

                   stride=stride-size
                          Configure  the  filesystem  for  a  RAID  array with
                          stride-size filesystem blocks. This is the number of
                          blocks  read or written to disk before moving to the
                          next disk, which is sometimes  referred  to  as  the
                          chunk   size.   This  mostly  affects  placement  of
                          filesystem metadata like bitmaps at mke2fs  time  to
                          avoid  placing them on a single disk, which can hurt
                          performance.  It may  also  be  used  by  the  block
                          allocator.

                   stripe_width=stripe-width
                          Configure  the  filesystem  for  a  RAID  array with
                          stripe-width filesystem blocks per stripe.  This  is
                          typically  stride-size * N, where N is the number of
                          data-bearing disks in the  RAID  (e.g.  for  RAID  5
                          there is one parity disk, so N will be the number of
                          disks in the array minus 1).  This allows the  block
                          allocator to prevent read-modify-write of the parity
                          in a RAID  stripe  if  possible  when  the  data  is
                          written.

                   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.

                   lazy_itable_init[= <0 to disable, 1 to enable>]
                          If enabled and the uninit_bg feature is enabled, the
                          inode table will not be fully initialized by mke2fs.
                          This speeds up filesystem initialization noticeably,
                          but it requires the kernel  to  finish  initializing
                          the filesystem in the background when the filesystem
                          is first mounted.  If the option value  is  omitted,
                          it defaults to 1 to enable lazy inode table zeroing.

                   lazy_journal_init[= <0 to disable, 1 to enable>]
                          If  enabled,  the  journal  inode  will not be fully
                          zeroed out by mke2fs.   This  speeds  up  filesystem
                          initialization  noticeably,  but  carries some small
                          risk if the system crashes before  the  journal  has
                          been  overwritten  entirely one time.  If the option
                          value is omitted, it defaults to 1  to  enable  lazy
                          journal inode zeroing.

                   test_fs
                          Set  a  flag in the filesystem superblock indicating
                          that it may be  mounted  using  experimental  kernel
                          code, such as the ext4dev filesystem.

                   discard
                          Attempt  to  discard blocks at mkfs time (discarding
                          blocks initially is useful on  solid  state  devices
                          and  sparse  /  thin-provisioned  storage). When the
                          device advertises that discard also zeroes data (any
                          subsequent  read  after the discard and before write
                          returns zero), then mark  all  not-yet-zeroed  inode
                          tables  as  zeroed.  This  significantly  speeds  up
                          filesystem initialization. This is set as default.

                   nodiscard
                          Do not attempt to discard blocks at mkfs time.

                   quotatype
                          Specify which quota type ('usr' or 'grp') is  to  be
                          initialized.  This  option  has  any  effect only if
                          quota feature is set. Without this extended  option,
                          the  default behavior is to initialize both user and
                          group quotas.

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

       -F     Force mke2fs to create  a  filesystem,  even  if  the  specified
              device is not a partition on a block special device, or if other
              parameters do not make sense.   In  order  to  force  mke2fs  to
              create  a filesystem even if the filesystem appears to be in use
              or is mounted (a truly dangerous thing to do), this option  must
              be specified twice.

       -g blocks-per-group
              Specify  the  number  of  blocks  in  a  block  group.  There is
              generally no reason for 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 -E option rather
              than manipulating the number of blocks per group.)  This  option
              is generally used by developers who are developing test cases.

       -G number-of-groups
              Specify  the number of block groups that will be packed together
              to create a larger virtual block group (or "flex_bg  group")  in
              an  ext4  filesystem.   This  improves  meta-data  locality  and
              performance on meta-data heavy workloads.  The number of  groups
              must  be  a  power of 2 and may only be specified if the flex_bg
              filesystem feature is enabled.

       -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 in that case more  inodes  would  be  made
              than  can  ever  be  used.  Be warned that it is not possible to
              expand the number of inodes on a filesystem after it is created,
              so be careful deciding the correct value for this parameter.

       -I inode-size
              Specify  the  size  of  each  inode  in  bytes.   mke2fs creates
              256-byte inodes by default.  In kernels after  2.6.10  and  some
              earlier  vendor  kernels it is possible to utilize inodes larger
              than  128  bytes  to  store  extended  attributes  for  improved
              performance.   The  inode-size value must be a power of 2 larger
              or equal to 128.  The larger the inode-size the more  space  the
              inode  table  will consume, and this reduces the usable space in
              the filesystem  and  can  also  negatively  impact  performance.
              Extended  attributes stored in large inodes are not visible with
              older kernels, and such filesystems will not be  mountable  with
              2.4  kernels  at  all.   It is not possible to change this value
              after the filesystem is created.

       -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 10,240,000
                          filesystem blocks or half the total file system size
                          (whichever is smaller)

                   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
                          multiple  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,
                          external-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
              automatically 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 last-mounted-directory
              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
              Overrides  the  default  value of the "creator operating system"
              field of the filesystem.  The creator field is set by default to
              the name of the OS the mke2fs executable was compiled for.

       -O feature[,...]
              Create   a   filesystem  with  the  given  features  (filesystem
              options),  overriding  the  default  filesystem  options.    The
              features  that  are  enabled  by  default  are  specified by the
              base_features relation, either in the [defaults] section in  the
              /etc/mke2fs.conf   configuration  file,  or  in  the  [fs_types]
              subsections for the usage types as specified by the  -T  option,
              further   modified   by  the  features  relation  found  in  the
              [fs_types] subsections for the filesystem and usage types.   See
              the mke2fs.conf(5) manual page for more details.  The filesystem
              type-specific configuration  setting  found  in  the  [fs_types]
              section will override the global default found in [defaults].

              The  filesystem  feature set will be further edited using either
              the feature set specified by this option, or if this  option  is
              not  given,  by the default_features relation for the filesystem
              type  being  created,  or  in  the  [defaults]  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
              feature,  simply  prefix  the  feature  name with a  caret ('^')
              character.  The pseudo-filesystem feature "none" will clear  all
              filesystem features.

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

                   extent Instead of  using  the  indirect  block  scheme  for
                          storing the location of data blocks in an inode, use
                          extents instead.  This  is  a  much  more  efficient
                          encoding   which   speeds   up   filesystem  access,
                          especially for large files.

                   filetype
                          Store file type information in directory entries.

                   flex_bg
                          Allow  the  per-block  group  metadata   (allocation
                          bitmaps  and  inode tables) to be placed anywhere on
                          the storage media.  In addition, mke2fs  will  place
                          the  per-block  group  metadata together starting at
                          the first block group of each "flex_bg group".   The
                          size of the flex_bg group can be specified using the
                          -G option.

                   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.

                   large_file
                          Filesystem  can  contain files that are greater than
                          2GB.  (Modern kernels set this feature automatically
                          when a file > 2GB is created.)

                   quota  Create  quota  inodes  (inode#  3  for userquota and
                          inode# 4 for  group  quota)  and  set  them  in  the
                          superblock.   With  this feature, the quotas will be
                          enabled  automatically  when   the   filesystem   is
                          mounted.

                   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 the resize extended option.

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

                   uninit_bg
                          Create  a filesystem without initializing all of the
                          block groups.  This feature also  enables  checksums
                          and    highest-inode-used    statistics    in   each
                          blockgroup.  This feature can  speed  up  filesystem
                          creation  time  noticeably  (if  lazy_itable_init is
                          enabled),  and   can   also   reduce   e2fsck   time
                          dramatically.   It  is  only  supported  by the ext4
                          filesystem in recent Linux kernels.

       -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
              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  the filesystem type (i.e., ext2, ext3, ext4, etc.) that
              is to be created.  If this option is not specified, mke2fs  will
              pick  a default either via how the command was run (for example,
              using a name of the form mkfs.ext2, mkfs.ext3, etc.)  or  via  a
              default  as  defined  by  the  /etc/mke2fs.conf(5)  file.   This
              option controls which filesystem options are  used  by  default,
              based     on     the    fstypes    configuration    stanza    in
              /etc/mke2fs.conf(5).

              If the -O option is used to explicitly add or remove  filesystem
              options  that should be set in the newly created filesystem, the
              resulting filesystem may not be supported by the  requested  fs-
              type.  (e.g., "mke2fs -t ext3 -O extent /dev/sdXX" will create a
              filesystem that is not supported by the ext3  implementation  as
              found  in  the Linux kernel; and "mke2fs -t ext3 -O ^has_journal
              /dev/hdXX" will create a filesystem that does not have a journal
              and  hence  will not be supported by the ext3 filesystem code in
              the Linux kernel.)

       -T usage-type[,...]
              Specify how the filesystem is going to be used, so  that  mke2fs
              can  choose  optimal  filesystem  parameters  for that use.  The
              usage types that are supported are defined in the  configuration
              file  /etc/mke2fs.conf(5).   The  user  may  specify one or more
              usage types using a comma separated list.

              If this option is is not specified, mke2fs will  pick  a  single
              default  usage  type  based  on the size of the filesystem to be
              created.  If the filesystem size is less  than  or  equal  to  3
              megabytes,  mke2fs  will use the filesystem type floppy.  If the
              filesystem size is greater than 3 but less than or equal to  512
              megabytes, mke2fs(8) will use the filesystem type small.  If the
              filesystem size is greater than or equal to 4 terabytes but less
              than  16  terabytes, mke2fs(8) will use the filesystem type big.
              If the filesystem size is greater than or equal to 16 terabytes,
              mke2fs(8)   will  use  the  filesystem  type  huge.   Otherwise,
              mke2fs(8) will use the default filesystem type default.

       -U UUID
              Create the filesystem with the specified UUID.

       -v     Verbose execution.

       -V     Print the version number of mke2fs and exit.

ENVIRONMENT

       MKE2FS_SYNC
              If set to non-zero integer value, its value is used to determine
              how often sync(2) is called during inode table initialization.

       MKE2FS_CONFIG
              Determines   the   location   of  the  configuration  file  (see
              mke2fs.conf(5)).

       MKE2FS_FIRST_META_BG
              If set to non-zero integer value, its value is used to determine
              first meta block group. This is mostly for debugging purposes.

       MKE2FS_DEVICE_SECTSIZE
              If set to non-zero integer value, its value is used to determine
              physical sector size of the device.

       MKE2FS_SKIP_CHECK_MSG
              If set, do not show the message of  filesystem  automatic  check
              caused by mount count or check interval.

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 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)