mke2fs.conf(5)



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 filesystems.

       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
       below:

            [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 an 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.

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

       proceed_delay
              If this relation is set to a positive integer,  then  if  mke2fs
              will  proceed  after waiting proceed_delay seconds, after asking
              the user for permission to proceed, 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.

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

       base_features
              This relation  specifies  the  filesystems  features  which  are
              enabled  in  newly created filesystems.  It may be overridden by
              the base_features relation found in the filesystem or usage type
              subsection of the [fs_types] stanza.

       default_features
              This  relation  specifies a set of features that should be added
              or removed to the features listed in the base_features relation.
              It may be overridden by the filesystem-specific default_features
              in the filesystem or usage type subsection of [fs_types], and by
              the -O command-line option to mke2fs(8).

       enable_periodic_fsck
              This  boolean  relation  specifies  whether  periodic filesystem
              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).

       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
              filesystem image because the inode table isn't being initialized
              lazily.

       fs_type
              This  relation specifies the default filesystem 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
              filesystem  type,  mke2fs  will use a default filesystem 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
              environment  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 filesystem-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 filesystem type or usage type
       which can be specified via the -t or -T options to  mke2fs(8),  respec-
       tively.

       The  mke2fs  program constructs a list of fs_types by concatenating the
       filesystem 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 filesystem 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 filesys-
       tem  type  of  ext4  will be used.  If the filesystem is smaller than 3
       megabytes, and no usage type is  specified,  then  mke2fs  will  use  a
       default  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 filesystem  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 filesystem, 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
       extents and flex_bg features, and finally  the  configuration  relation
       fs_types.floppy.features would remove the resize_inode feature, result-
       ing in a filesystem feature set consisting of the  sparse_super,  file-
       type, dir_index, extents_and flex_bg features.

       For  each  filesystem  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 filesystem 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).

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

                   continue    Continue normal execution.

                   remount-ro  Remount filesystem 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 filesystem.  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.

       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 filesystem initializa-
              tion noticeably, but it requires the kernel to finish initializ-
              ing the filesystem in the  background  when  the  filesystem  is
              first mounted.

       journal_location
              This relation specifies the location of the journal.

       num_backup_sb
              This   relation   indicates   whether   file  systems  with  the
              sparse_super2 feature enabled should be created with 0, 1, or  2
              backup superblocks.

       packed_meta_blocks
              This  boolean  relation specifes 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 filesystem
              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 filesystems 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  filesystem.   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
              filesystem 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
              default  extended  options used by mke2fs(8) on a per-filesystem
              type basis.

       discard
              This boolean relation specifies  whether  the  mke2fs(8)  should
              attempt to discard device prior to filesystem 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.

       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
              relation  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.

       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
              untrusted  user  programs,  unless  the  device  supports a dis-
              card/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.

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 1.43.1           June 2016                    mke2fs.conf(5)

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