Provided by: e2fsprogs_1.44.1-1_amd64 bug

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  example 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 spaces.  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 character).

       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 writing 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.

       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
       section 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), respectively.

       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  filesystem  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,  resulting  in  a  filesystem  feature  set   consisting   of   the
       sparse_super, filetype, 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 section:

       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 subsections define the  base_features  relation,
              only the last will be used by 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).

       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 following:

                   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 constructed 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.

       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.

       default_features
              This relation specifies set of features which should be enabled or  disabled  after
              applying  the  features listed in the base_features 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
              initialization noticeably, but it requires the kernel to  finish  initializing  the
              filesystem in the background when the filesystem 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 filesystem  initialization  noticeably,  but  carries  some
              small  risk  if the system crashes before the journal has been overwritten 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_super2 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 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 algorithms 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 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.

       options
              This  relation  specifies  additional  extended  options which should be treated by
              mke2fs(8) as if they were prepended to the argument 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.  The extent tree blocks for these  pre-allocated  files
              will  be  placed near the beginning 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-allocated files will be contiguous.

       hugefiles_dir
              This relation specifies the directory where huge files are created, relative to the
              filesystem 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 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 multiple of the requested alignment.  If
              this relation is not specified, no alignment requirement will  be  imposed  on  the
              huge files.

       hugefiles_align_disk
              This  relations specifies whether the alignment should be relative 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  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.

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)