Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
mke2fs.conf(5)		      File Formats Manual		mke2fs.conf(5)

NAME
       mke2fs.conf - Configuration file	for mke2fs

DESCRIPTION
       mke2fs.conf  is	the configuration file for mke2fs(8).  It controls the
       default parameters used by mke2fs(8) when it is creating	ext2, ext3, or
       ext4 file systems.

       The  mke2fs.conf	 file uses an INI-style	format.	 Stanzas, or top-level
       sections, are delimited by square braces: [ ].	Within	each  section,
       each  line  defines  a  relation, which assigns tags to values, or to a
       subsection, which contains further relations or subsections.  An	 exam-
       ple of the INI-style format used	by this	configuration file follows be-
       low:

	    [section1]
		 tag1 =	value_a
		 tag1 =	value_b
		 tag2 =	value_c

	    [section 2]
		 tag3 =	{
		      subtag1 =	subtag_value_a
		      subtag1 =	subtag_value_b
		      subtag2 =	subtag_value_c
		 }
		 tag1 =	value_d
		 tag2 =	value_e
	    }

       Comments	are delimited by a semicolon (';') or a	hash  ('#')  character
       at  the beginning of the	comment, and are terminated by the end of line
       character.

       Tags and	values must be quoted using double quotes if they contain spa-
       ces.   Within  a	 quoted	string,	the standard backslash interpretations
       apply: "\n" (for	the newline character),	"\t" (for the tab  character),
       "\b" (for the backspace character), and "\\" (for the backslash charac-
       ter).

       Some relations expect a boolean value.  The parser is quite liberal  on
       recognizing  ``yes'',  '`y'', ``true'', ``t'', ``1'', ``on'', etc. as a
       boolean true value,  and	 ``no'',  ``n'',  ``false'',  ``nil'',	``0'',
       ``off'' as a boolean false value.

       The  following  stanzas are used	in the mke2fs.conf file.  They will be
       described in more detail	in future sections of this document.

       [options]
	      Contains relations which influence how mke2fs behaves.

       [defaults]
	      Contains relations which define the default parameters  used  by
	      mke2fs(8).   In  general,	 these defaults	may be overridden by a
	      definition in the	fs_types stanza, or by a  command-line	option
	      provided by the user.

       [fs_types]
	      Contains relations which define defaults that should be used for
	      specific file system and usage types.  The file system type  and
	      usage type can be	specified explicitly using the -tand-T options
	      to mke2fs(8), respectively.

       [devices]
	      Contains relations which define defaults for specific devices.

THE [options] STANZA
       The following relations are defined in the [options] stanza.

       proceed_delay
	      If this relation is set to a positive integer, then mke2fs  will
	      wait  proceed_delay seconds after	asking the user	for permission
	      to proceed and then continue, even if the	user has not  answered
	      the question.  Defaults to 0, which means	to wait	until the user
	      answers the question one way or another.

       sync_kludge
	      If this relation is set to a positive integer, then while	 writ-
	      ing  the	inode  table, mke2fs will request the operating	system
	      flush out	pending	writes to initialize  the  inode  table	 every
	      sync_kludge  block groups.   This	is needed to work around buggy
	      kernels that don't handle	writeback throttling correctly.

THE [defaults] STANZA
       The following relations are defined in the [defaults] stanza.

       creator_os
	      This relation specifies the "creator operating system"  for  the
	      file system unless it is overriden on the	command	line.  The de-
	      fault value is the OS for	which the mke2fs executable  was  com-
	      piled.

       fs_type
	      This relation specifies the default file system type if the user
	      does not specify it via the -t  option,  or  if  mke2fs  is  not
	      started  using a program name of the form	mkfs.fs-type.  If both
	      the user and the mke2fs.conf file	do not specify a default  file
	      system  type, mke2fs will	use a default file system type of ext3
	      if a journal was requested via a command-line option, or ext2 if
	      not.

       undo_dir
	      This relation specifies the directory where the undo file	should
	      be stored.  It can be overridden via the E2FSPROGS_UNDO_DIR  en-
	      vironment	 variable.   If	 the  directory	location is set	to the
	      value none, mke2fs will not create an undo file.

       In addition, any	tags that can be specified in a	per-file  system  tags
       subsection  as  defined	below (e.g., blocksize,	hash_alg, inode_ratio,
       inode_size, reserved_ratio, etc.) can also be specified in the defaults
       stanza  to  specify  the	 default value to be used if the user does not
       specify one on the command line,	and the	file system-type specific sec-
       tion of the configuration file does not specify a default value.

THE [fs_types] STANZA
       Each  tag  in  the  [fs_types] stanza names a file system type or usage
       type which can be specified via the -t or -T options to mke2fs(8),  re-
       spectively.

       The  mke2fs  program constructs a list of fs_types by concatenating the
       file system type	(i.e., ext2, ext3, etc.) with  the  usage  type	 list.
       For  most  configuration	 options, mke2fs will look for a subsection in
       the [fs_types] stanza corresponding with	each entry in the  constructed
       list, with later	entries	overriding earlier file	system or usage	types.
       For example, consider the following mke2fs.conf fragment:

       [defaults]
	    base_features = sparse_super,filetype,resize_inode,dir_index
	    blocksize =	4096
	    inode_size = 256
	    inode_ratio	= 16384

       [fs_types]
	    ext3 = {
		 features = has_journal
	    }
	    ext4 = {
		 features = extents,flex_bg
		 inode_size = 256
	    }
	    small = {
		 blocksize = 1024
		 inode_ratio = 4096
	    }
	    floppy = {
		 features = ^resize_inode
		 blocksize = 1024
		 inode_size = 128
	    }

       If mke2fs started with a	program	name of	 mke2fs.ext4,  then  the  file
       system type of ext4 will	be used.  If the file system is	smaller	than 3
       megabytes, and no usage type is specified, then mke2fs will use	a  de-
       fault usage type	of floppy.  This results in an fs_types	list of	"ext4,
       floppy".	  Both the ext4	subsection and the floppy subsection define an
       inode_size  relation,  but since	the later entries in the fs_types list
       supersede   earlier   ones,    the    configuration    parameter	   for
       fs_types.floppy.inode_size  will	be used, so the	file system  will have
       an inode	size of	128.

       The exception to	this resolution	is the features	tag, which specifies a
       set  of	changes	 to the	features used by the file system, and which is
       cumulative.  So in the above example, first the configuration  relation
       defaults.base_features  would  enable  an  initial feature set with the
       sparse_super, filetype, resize_inode, and dir_index  features  enabled.
       Then configuration relation fs_types.ext4.features would	enable the ex-
       tents and flex_bg features,  and	 finally  the  configuration  relation
       fs_types.floppy.features	would remove the resize_inode feature, result-
       ing in a	file system feature set	consisting of the sparse_super,	 file-
       type, dir_index,	extents_and flex_bg features.

       For  each  file	system	type,  the  following tags may be used in that
       fs_type's subsection.   These tags may also be used in the default sec-
       tion:

       base_features
	      This relation specifies the features which are initially enabled
	      for this file system type.  Only one base_features will be used,
	      so if there are multiple entries in the fs_types list whose sub-
	      sections define the base_features	relation, only the  last  will
	      be used by mke2fs(8).

       enable_periodic_fsck
	      This  boolean  relation  specifies  whether periodic file	system
	      checks should be enforced	at boot	time.  If set to true,	checks
	      will  be	forced	every  180  days,  or after a random number of
	      mounts.  These values may	be changed later via  the  -i  and  -c
	      command-line options to tune2fs(8).

       errors Change the behavior of the kernel	code when errors are detected.
	      In all cases, a file system error	will cause e2fsck(8) to	 check
	      the file system on the next boot.	 errors	can be one of the fol-
	      lowing:

		   continue    Continue	normal execution.

		   remount-ro  Remount file system read-only.

		   panic       Cause a kernel panic.

       features
	      This relation specifies a	comma-separated	list of	features  edit
	      requests	which  modify  the  feature set	used by	the newly con-
	      structed file system.  The syntax	is the same as the -O command-
	      line  option to mke2fs(8); that is, a feature can	be prefixed by
	      a	caret ('^') symbol to disable a	named feature.	 Each  feature
	      relation	specified  in the fs_types list	will be	applied	in the
	      order found in the fs_types list.

       force_undo
	      This boolean relation, if	set to a value of true,	forces	mke2fs
	      to  always  try  to  create  an undo file, even if the undo file
	      might be huge and	it might extend	the time to  create  the  file
	      system  image  because  the  inode table isn't being initialized
	      lazily.

       default_features
	      This relation specifies set of features which should be  enabled
	      or  disabled after applying the features listed in the base_fea-
	      tures and	features relations.  It	may be overridden  by  the  -O
	      command-line option to mke2fs(8).

       auto_64-bit_support
	      This  relation  is  a  boolean which specifies whether mke2fs(8)
	      should automatically add the 64bit  feature  if  the  number  of
	      blocks  for the file system requires this	feature	to be enabled.
	      The resize_inode feature is also automatically disabled since it
	      doesn't support 64-bit block numbers.

       default_mntopts
	      This relation specifies the set of mount options which should be
	      enabled by default.  These may be	changed	at a later  time  with
	      the -o command-line option to tune2fs(8).

       blocksize
	      This  relation  specifies	the default blocksize if the user does
	      not specify a blocksize on the command line.

       lazy_itable_init
	      This boolean relation specifies whether the inode	 table	should
	      be  lazily  initialized.	 It  only has meaning if the uninit_bg
	      feature  is  enabled.   If  lazy_itable_init  is	true  and  the
	      uninit_bg	feature	is enabled,  the inode table will not be fully
	      initialized by mke2fs(8).	 This speeds up	file  system  initial-
	      ization  noticeably,  but	 it requires the kernel	to finish ini-
	      tializing	the file system	in the background when the file	system
	      is first mounted.

       lazy_journal_init
	      This boolean relation specifies whether the journal inode	should
	      be lazily	initialized. It	only has meaning  if  the  has_journal
	      feature  is  enabled.  If	lazy_journal_init is true, the journal
	      inode will not be	fully zeroed out by mke2fs.   This  speeds  up
	      file  system  initialization  noticeably,	but carries some small
	      risk if the system crashes before	the journal has	been overwrit-
	      ten entirely one time.

       journal_location
	      This relation specifies the location of the journal.

       num_backup_sb
	      This relation indicates whether file systems with	the sparse_su-
	      per2 feature enabled should be created with 0, 1,	 or  2	backup
	      superblocks.

       packed_meta_blocks
	      This  boolean relation specifies whether the allocation bitmaps,
	      inode table, and journal should be located at the	 beginning  of
	      the file system.

       inode_ratio
	      This relation specifies the default inode	ratio if the user does
	      not specify one on the command line.

       inode_size
	      This relation specifies the default inode	size if	the user  does
	      not specify one on the command line.

       reserved_ratio
	      This  relation  specifies	 the default percentage	of file	system
	      blocks reserved for the super-user, if the user does not specify
	      one on the command line.

       hash_alg
	      This  relation specifies the default hash	algorithm used for the
	      new file systems with hashed b-tree  directories.	  Valid	 algo-
	      rithms accepted are: legacy, half_md4, and tea.

       flex_bg_size
	      This  relation specifies the number of block groups that will be
	      packed together to create	one large virtual block	 group	on  an
	      ext4  file system.  This improves	meta-data locality and perfor-
	      mance on meta-data heavy workloads.  The number of  groups  must
	      be  a  power  of 2 and may only be specified if the flex_bg file
	      system feature is	enabled.

       options
	      This relation specifies additional extended options which	should
	      be  treated  by mke2fs(8)	as if they were	prepended to the argu-
	      ment of the -E option.  This can be used to  configure  the  de-
	      fault  extended  options	used by	mke2fs(8) on a per-file	system
	      type basis.

       discard
	      This boolean relation specifies whether the mke2fs(8) should at-
	      tempt to discard device prior to file system creation.

       cluster_size
	      This relation specifies the default cluster size if the bigalloc
	      file system feature is enabled.  It can be overridden via	the -C
	      command line option to mke2fs(8)

       make_hugefiles
	      This  boolean  relation  enables	the  creation of pre-allocated
	      files as part of formatting the file system.   The  extent  tree
	      blocks for these pre-allocated files will	be placed near the be-
	      ginning of the file system, so that if all of the	other metadata
	      blocks  are  also	 configured to be placed near the beginning of
	      the file system (by disabling the	backup superblocks, using  the
	      packed_meta_blocks option, etc.),	the data blocks	of the pre-al-
	      located files will be contiguous.

       hugefiles_dir
	      This relation specifies the directory where huge files are  cre-
	      ated, relative to	the file system	root.

       hugefiles_uid
	      This  relation  controls the user	ownership for all of the files
	      and directories created by the make_hugefiles feature.

       hugefiles_gid
	      This relation controls the group ownership for all of the	 files
	      and directories created by the make_hugefiles feature.

       hugefiles_umask
	      This  relation  specifies	the umask used when creating the files
	      and directories by the make_hugefiles feature.

       num_hugefiles
	      This relation specifies the number of huge files to be  created.
	      If  this	relation  is not specified, or is set to zero, and the
	      hugefiles_size relation is non-zero,  then  make_hugefiles  will
	      create  as  many	huge  files as can fit to fill the entire file
	      system.

       hugefiles_slack
	      This relation specifies how much space should  be	 reserved  for
	      other files.

       hugefiles_size
	      This relation specifies the size of the huge files.  If this re-
	      lation is	not specified, the default is to fill the entire  file
	      system.

       hugefiles_align
	      This relation specifies the alignment for	the start block	of the
	      huge files.  It also forces the size of huge files to be a  mul-
	      tiple of the requested alignment.	 If this relation is not spec-
	      ified, no	alignment requirement will  be	imposed	 on  the  huge
	      files.

       hugefiles_align_disk
	      This  relations  specifies whether the alignment should be rela-
	      tive to the beginning of	the  hard  drive  (assuming  that  the
	      starting	offset	of the partition is available to mke2fs).  The
	      default value is false, which will cause hugefile	 alignment  to
	      be relative to the beginning of the file system.

       hugefiles_name
	      This relation specifies the base file name for the huge files.

       hugefiles_digits
	      This relation specifies the (zero-padded)	width of the field for
	      the huge file number.

       warn_y2038_dates
	      This boolean relation specifies wheather	mke2fs	will  issue  a
	      warning when creating a file system with 128 byte	inodes (and so
	      therefore	will not support dates after January 19th, 2038).  The
	      default  value  is true, except for file systems created for the
	      GNU Hurd since it	only supports 128-byte inodes.

       zero_hugefiles
	      This boolean relation specifies whether or not zero blocks  will
	      be  written  to  the hugefiles while mke2fs(8) is	creating them.
	      By default, zero blocks will be written to  the  huge  files  to
	      avoid  stale  data  from being made available to potentially un-
	      trusted user programs, unless the	device supports	a discard/trim
	      operation	which will take	care of	zeroing	the device blocks.  By
	      setting zero_hugefiles  to  false,  this	step  will  always  be
	      skipped,	which  can  be useful if it is known that the disk has
	      been previously erased, or if the	user programs that  will  have
	      access to	the huge files are trusted to not reveal stale data.

       encoding
	      This  relation  defines the file name encoding to	be used	if the
	      casefold feature is enabled.   Currently the only	valid encoding
	      is  utf8-12.1  or	 utf8,	which requests the most	recent Unicode
	      version; since 12.1 is the only available	Unicode	version,  utf8
	      and  utf8-12.1  have the same result.  encoding_flags This rela-
	      tion defines encoding-specific flags.  For utf8  encodings,  the
	      only available flag is strict, which will	cause attempts to cre-
	      ate file names containing	invalid	Unicode	characters to  be  re-
	      jected by	the kernel.  Strict mode is not	enabled	by default.

THE [devices] STANZA
       Each  tag  in the [devices] stanza names	device name so that per-device
       defaults	can be specified.

       fs_type
	      This relation specifies the default parameter for	the -t option,
	      if this option isn't specified on	the command line.

       usage_types
	      This relation specifies the default parameter for	the -T option,
	      if this option isn't specified on	the command line.

FILES
       /etc/mke2fs.conf
	      The configuration	file for mke2fs(8).

SEE ALSO
       mke2fs(8)

E2fsprogs version 1.46.4	  August 2021			mke2fs.conf(5)

NAME | DESCRIPTION | THE [options] STANZA | THE [defaults] STANZA | THE [fs_types] STANZA | THE [devices] STANZA | FILES | SEE ALSO

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=mke2fs.conf&sektion=5&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help