2 .\" Copyright 2006 by Theodore Ts'o. All Rights Reserved.
3 .\" This file may be copied under the terms of the GNU Public License.
5 .TH mke2fs.conf 5 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
7 mke2fs.conf \- Configuration file for mke2fs
10 is the configuration file for
12 It controls the default parameters used by
14 when it is creating ext2 or ext3 filesystems.
18 file uses an INI-style format. Stanzas, or top-level sections, are
19 delimited by square braces: [ ]. Within each section, each line
20 defines a relation, which assigns tags to values, or to a subsection,
21 which contains further relations or subsections.
22 .\" Tags can be assigned multiple values
23 An example of the INI-style format used by this configuration file
38 subtag1 = subtag_value_a
40 subtag1 = subtag_value_b
42 subtag2 = subtag_value_c
52 Comments are delimited by a semicolon (';') or a hash ('#') character
53 at the beginning of the comment, and are terminated by the end of
56 Tags and values must be quoted using double quotes if they contain
57 spaces. Within a quoted string, the standard backslash interpretations
58 apply: "\en" (for the newline character),
59 "\et" (for the tab character), "\eb" (for the backspace character),
60 and "\e\e" (for the backslash character).
62 The following stanzas are used in the
64 file. They will be described in more detail in future sections of this
68 Contains relations which define the default parameters
71 In general, these defaults may be overridden by a definition in the
73 stanza, or by an command-line option provided by the user.
76 Contains relations which define defaults that should be used for specific
77 filesystem types. The filesystem type can be specified explicitly using
82 .SH THE [defaults] STANZA
83 The following relations are defined in the
88 This relation specifies the filesystems features which are enabled in
89 newly created filesystems. It may be overridden by the
91 relation found in the filesystem or usage type subsection of
97 This relation specifies a set of features that should be added or
98 removed to the features listed in the
100 relation. It may be overridden by the filesystem-specific
102 in the filesystem or usage type subsection of
111 This relation, if set to a boolean value of true, forces
113 to always try to create an undo file, even if the undo file might be
114 huge and it might extend the time to create the filesystem image
115 because the inode table isn't being initialized lazily.
118 This relation specifies the default filesystem type if the user does not
123 is not started using a program name of the form
124 .BI mkfs. fs-type\fR.
125 If both the user and the
127 file does not specify a default filesystem type, mke2fs will use a
128 default filesystem type of
130 if a journal was requested via a command-line option, or
135 This relation specifies the default blocksize if the user does not
136 specify a blocksize on the command line, and the filesystem-type
137 specific section of the configuration file does not specify a blocksize.
140 This relation specifies the default inode ratio if the user does not
141 specify one on the command line, and the filesystem-type
142 specific section of the configuration file does not specify a default
146 This relation specifies the default inode size if the user does not
147 specify one on the command line, and the filesystem-type
148 specific section of the configuration file does not specify a default
152 This relation specifies the directory where the undo file should be
153 stored. It can be overriden via the
154 .B E2FSPROGS_UNDO_DIR
155 environemnt variable. If the directory location is set to the value
158 will not create an undo file.
159 .SH THE [fs_types] STANZA
162 stanza names a filesystem type or usage type which can be specified via the
172 program constructs a list of fs_types by concatenating the filesystem
173 type (i.e., ext2, ext3, etc.) with the usage type list. For most
174 configuration options,
176 will look for a subsection in the
178 stanza corresponding with each entry in the constructed list, with later
179 entries overriding earlier filesystem or usage types.
181 example, consider the following
187 base_features = sparse_super,filetype,resize_inode,dir_index
201 features = has_journal
207 features = extents,flex_bg
223 features = ^resize_inode
231 If mke2fs started with a program name of
233 then the filesystem type of ext4 will be used. If the filesystem is
234 smaller than 3 megabytes, and no usage type is specified, then
239 This results in an fs_types list of "ext4, floppy". Both the ext4
240 subsection and the floppy subsection define an
242 relation, but since the later entries in the fs_types list supercede
243 earlier ones, the configuration parameter for fs_types.floppy.inode_size
244 will be used, so the filesystem will have an inode size of 128.
246 The exception to this resolution is the
248 tag, which is specifies a set of changes to the features used by the
249 filesystem, and which is cumulative. So in the above example, first
250 the configuration relation defaults.base_features would enable an
251 initial feature set with the sparse_super, filetype, resize_inode, and
252 dir_index features enabled. Then configuration relation
253 fs_types.ext4.features would enable the extents and flex_bg
254 features, and finally the configuration relation
255 fs_types.floppy.features would remove
256 the resize_inode feature, resulting in a filesystem feature set
257 consisting of the sparse_super, filetype, resize_inode, dir_index,
258 extents_and flex_bg features.
260 For each filesystem type, the following tags may be used in that
261 fs_type's subsection:
264 This relation specifies the features which are initially enabled for this
265 filesystem type. Only one
267 will be used, so if there are multiple entries in the fs_types list
268 whose subsections define the
270 relation, only the last will be used by
274 This relation specifies a comma-separated list of features edit
275 requests which modify the feature set
276 used by the newly constructed filesystem. The syntax is the same as the
278 command-line option to
280 that is, a feature can be prefixed by a caret ('^') symbol to disable
281 a named feature. Each
283 relation specified in the fs_types list will be applied in the order
284 found in the fs_types list.
287 This relation specifies set of features which should be enabled or
288 disabled after applying the features listed in the
292 relations. It may be overridden by the
294 command-line option to
298 This relation specifies the default blocksize if the user does not
299 specify a blocksize on the command line.
302 This relation is a boolean which specifies whether the inode table should
303 be lazily initialized. It only has meaning if the uninit_bg feature is
304 enabled. If lazy_itable_init is true and the uninit_bg feature is
305 enabled, the inode table will
306 not fully initialized by
308 This speeds up filesystem
309 initialization noitceably, but it requires the kernel to finish
310 initializing the filesystem in the background when the filesystem is
314 This relation specifies the default inode ratio if the user does not
315 specify one on the command line.
318 This relation specifies the default inode size if the user does not
319 specify one on the command line.
322 This relation specifies the number of block goups that will be packed
323 together to create one large virtual block group on an ext4 filesystem.
324 This improves meta-data locality and performance on meta-data heavy
325 workloads. The number of goups must be a power of 2 and may only be
326 specified if the flex_bg filesystem feature is enabled.
328 This relation specifies additional extended options which should be
331 as if they were prepended to the argument of the
333 option. This can be used to configure the default extended options used
336 on a per-filesystem type basis.
340 The configuration file for