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3839e657 | 1 | .\" -*- nroff -*- |
a418d3ad TT |
2 | .\" Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved. |
3 | .\" This file may be copied under the terms of the GNU Public License. | |
98794d0e | 4 | .\" |
74becf3c | 5 | .TH MKE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" |
3839e657 | 6 | .SH NAME |
4f858546 | 7 | mke2fs \- create an ext2/ext3/ext4 filesystem |
3839e657 TT |
8 | .SH SYNOPSIS |
9 | .B mke2fs | |
10 | [ | |
11 | .B \-c | |
98794d0e | 12 | | |
3839e657 | 13 | .B \-l |
1e3472c5 | 14 | .I filename |
3839e657 TT |
15 | ] |
16 | [ | |
17 | .B \-b | |
1e3472c5 | 18 | .I block-size |
3839e657 TT |
19 | ] |
20 | [ | |
4407ea3b DW |
21 | .B \-d |
22 | .I root-directory | |
23 | ] | |
24 | [ | |
37c8db7b TT |
25 | .B \-D |
26 | ] | |
27 | [ | |
5e05541a TT |
28 | .B \-g |
29 | .I blocks-per-group | |
30 | ] | |
31 | [ | |
9ba40002 TT |
32 | .B \-G |
33 | .I number-of-groups | |
34 | ] | |
35 | [ | |
3839e657 | 36 | .B \-i |
1e3472c5 | 37 | .I bytes-per-inode |
3839e657 TT |
38 | ] |
39 | [ | |
067911ae AD |
40 | .B \-I |
41 | .I inode-size | |
42 | ] | |
43 | [ | |
85ef4ae8 | 44 | .B \-j |
dc2ec525 TT |
45 | ] |
46 | [ | |
47 | .B \-J | |
8ddaa66b | 48 | .I journal-options |
85ef4ae8 TT |
49 | ] |
50 | [ | |
5515e6b4 TT |
51 | .B \-N |
52 | .I number-of-inodes | |
53 | ] | |
54 | [ | |
a26ba650 | 55 | .B \-n |
2740156b TT |
56 | ] |
57 | [ | |
3839e657 | 58 | .B \-m |
1e3472c5 TT |
59 | .I reserved-blocks-percentage |
60 | ] | |
61 | [ | |
62 | .B \-o | |
63 | .I creator-os | |
3839e657 TT |
64 | ] |
65 | [ | |
98794d0e | 66 | .B \-O |
5c4c3876 | 67 | [^]\fIfeature\fR[,...] |
896938d5 TT |
68 | ] |
69 | [ | |
f3db3566 TT |
70 | .B \-q |
71 | ] | |
72 | [ | |
caf8ce4c TT |
73 | .B \-r |
74 | .I fs-revision-level | |
a29f4d30 TT |
75 | ] |
76 | [ | |
c6a44136 TT |
77 | .B \-E |
78 | .I extended-options | |
521e3685 TT |
79 | ] |
80 | [ | |
3839e657 TT |
81 | .B \-v |
82 | ] | |
f3db3566 | 83 | [ |
74becf3c TT |
84 | .B \-F |
85 | ] | |
86 | [ | |
1e3472c5 TT |
87 | .B \-L |
88 | .I volume-label | |
89 | ] | |
90 | [ | |
91 | .B \-M | |
92 | .I last-mounted-directory | |
93 | ] | |
94 | [ | |
f3db3566 TT |
95 | .B \-S |
96 | ] | |
818180cd | 97 | [ |
3d43836f TT |
98 | .B \-t |
99 | .I fs-type | |
100 | ] | |
101 | [ | |
50787ea2 | 102 | .B \-T |
3d43836f | 103 | .I usage-type |
50787ea2 TT |
104 | ] |
105 | [ | |
b0afdda1 TT |
106 | .B \-U |
107 | .I UUID | |
108 | ] | |
109 | [ | |
818180cd TT |
110 | .B \-V |
111 | ] | |
cd32129d DW |
112 | [ |
113 | .B \-e | |
114 | .I errors-behavior | |
115 | ] | |
2d291b3c DW |
116 | [ |
117 | .B \-z | |
118 | .I undo_file | |
119 | ] | |
1e3472c5 | 120 | .I device |
3839e657 | 121 | [ |
9ac2930c | 122 | .I fs-size |
3839e657 | 123 | ] |
48015ced | 124 | @JDEV@.sp |
8d641749 | 125 | @JDEV@.B "mke2fs \-O journal_dev" |
48015ced TT |
126 | @JDEV@[ |
127 | @JDEV@.B \-b | |
128 | @JDEV@.I block-size | |
129 | @JDEV@] | |
8d641749 | 130 | .\" No external-journal specific journal options yet (size is ignored) |
48015ced TT |
131 | .\" @JDEV@[ |
132 | .\" @JDEV@.B \-J | |
133 | .\" @JDEV@.I journal-options | |
134 | .\" @JDEV@] | |
135 | @JDEV@[ | |
136 | @JDEV@.B \-L | |
137 | @JDEV@.I volume-label | |
138 | @JDEV@] | |
139 | @JDEV@[ | |
140 | @JDEV@.B \-n | |
141 | @JDEV@] | |
142 | @JDEV@[ | |
143 | @JDEV@.B \-q | |
144 | @JDEV@] | |
145 | @JDEV@[ | |
146 | @JDEV@.B \-v | |
147 | @JDEV@] | |
8d641749 | 148 | @JDEV@.I external-journal |
2d15576d | 149 | @JDEV@[ |
9ac2930c | 150 | @JDEV@.I fs-size |
2d15576d | 151 | @JDEV@] |
3839e657 TT |
152 | .SH DESCRIPTION |
153 | .B mke2fs | |
4f858546 | 154 | is used to create an ext2, ext3, or ext4 filesystem, usually in a disk |
9ac2930c TT |
155 | partition (or file) named by |
156 | .IR device . | |
157 | .PP | |
158 | The file system size is specified by | |
159 | .IR fs-size . | |
160 | If | |
161 | .I fs-size | |
162 | does not have a suffix, it is interpreted as power-of-two kilobytes, | |
163 | unless the | |
164 | .B \-b | |
165 | .I blocksize | |
166 | option is specified, in which case | |
167 | .I fs-size | |
168 | is interpreted as the number of | |
169 | .I blocksize | |
170 | blocks. If the fs-size is suffixed by 'k', 'm', 'g', 't' | |
171 | (either upper-case or lower-case), then it is interpreted in | |
172 | power-of-two kilobytes, megabytes, gigabytes, terabytes, etc. | |
173 | If | |
174 | .I fs-size | |
175 | is omitted, | |
3839e657 | 176 | .B mke2fs |
9ac2930c TT |
177 | will create the file system based on the device size. |
178 | .PP | |
179 | If | |
180 | .B mke2fs | |
181 | is run as | |
182 | .B mkfs.XXX | |
183 | (i.e., | |
184 | .BR mkfs.ext2 , | |
185 | .BR mkfs.ext3 , | |
186 | or | |
187 | .BR mkfs.ext4 ) | |
188 | the option | |
189 | .B \-t | |
190 | .I XXX | |
191 | is implied; so | |
0072f8de | 192 | .B mkfs.ext3 |
9ac2930c TT |
193 | will create a file system for use with ext3, |
194 | .B mkfs.ext4 | |
195 | will create a file system for use with ext4, and so on. | |
de7a86e2 TT |
196 | .PP |
197 | The defaults of the parameters for the newly created filesystem, if not | |
198 | overridden by the options listed below, are controlled by the | |
199 | .B /etc/mke2fs.conf | |
200 | configuration file. See the | |
201 | .BR mke2fs.conf (5) | |
202 | manual page for more details. | |
3839e657 TT |
203 | .SH OPTIONS |
204 | .TP | |
caf8ce4c | 205 | .BI \-b " block-size" |
98794d0e | 206 | Specify the size of blocks in bytes. Valid block-size values are 1024, |
06968e7e | 207 | 2048 and 4096 bytes per block. If omitted, |
98794d0e | 208 | block-size is heuristically determined by the filesystem size and |
c5290fae | 209 | the expected usage of the filesystem (see the |
06968e7e | 210 | .B \-T |
98794d0e | 211 | option). If |
c5290fae | 212 | .I block-size |
eddf36ba | 213 | is preceded by a negative sign ('-'), then |
c6a44136 TT |
214 | .B mke2fs |
215 | will use heuristics to determine the | |
c5290fae | 216 | appropriate block size, with the constraint that the block size will be |
98794d0e | 217 | at least |
c5290fae TT |
218 | .I block-size |
219 | bytes. This is useful for certain hardware devices which require that | |
220 | the blocksize be a multiple of 2k. | |
3839e657 | 221 | .TP |
caf8ce4c | 222 | .B \-c |
3ed57c27 | 223 | Check the device for bad blocks before creating the file system. If |
98794d0e | 224 | this option is specified twice, then a slower read-write |
3ed57c27 | 225 | test is used instead of a fast read-only test. |
3839e657 | 226 | .TP |
0f680ee8 ZL |
227 | .B \-C " cluster-size" |
228 | Specify the size of cluster in bytes for filesystems using the bigalloc | |
229 | feature. Valid cluster-size values are from 2048 to 256M bytes per | |
9518b297 TT |
230 | cluster. This can only be specified if the bigalloc feature is |
231 | enabled. (See the | |
232 | .B ext4 (5) | |
233 | man page for more details about bigalloc.) The default cluster size if | |
234 | bigalloc is enabled is 16 times the block size. | |
0f680ee8 | 235 | .TP |
4407ea3b DW |
236 | .BI \-d " root-directory" |
237 | Copy the contents of the given directory into the root directory of the | |
238 | filesystem. | |
239 | .TP | |
37c8db7b TT |
240 | .B \-D |
241 | Use direct I/O when writing to the disk. This avoids mke2fs dirtying a | |
242 | lot of buffer cache memory, which may impact other applications running | |
243 | on a busy server. This option will cause mke2fs to run much more | |
244 | slowly, however, so there is a tradeoff to using direct I/O. | |
245 | .TP | |
cd32129d DW |
246 | .BI \-e " error-behavior" |
247 | Change the behavior of the kernel code when errors are detected. | |
248 | In all cases, a filesystem error will cause | |
249 | .BR e2fsck (8) | |
250 | to check the filesystem on the next boot. | |
251 | .I error-behavior | |
252 | can be one of the following: | |
253 | .RS 1.2i | |
254 | .TP 1.2i | |
255 | .B continue | |
256 | Continue normal execution. | |
257 | .TP | |
258 | .B remount-ro | |
259 | Remount filesystem read-only. | |
260 | .TP | |
261 | .B panic | |
262 | Cause a kernel panic. | |
263 | .RE | |
264 | .TP | |
c6a44136 TT |
265 | .BI \-E " extended-options" |
266 | Set extended options for the filesystem. Extended options are comma | |
267 | separated, and may take an argument using the equals ('=') sign. The | |
a26ba650 | 268 | .B \-E |
98794d0e | 269 | option used to be |
a26ba650 | 270 | .B \-R |
98794d0e | 271 | in earlier versions of |
c6a44136 | 272 | .BR mke2fs . |
98794d0e | 273 | The |
a26ba650 | 274 | .B \-R |
b769aaec AD |
275 | option is still accepted for backwards compatibility, but is deprecated. |
276 | The following extended options are supported: | |
c6a44136 TT |
277 | .RS 1.2i |
278 | .TP | |
0f5eba75 AD |
279 | .BI mmp_update_interval= interval |
280 | Adjust the initial MMP update interval to | |
281 | .I interval | |
282 | seconds. Specifying an | |
283 | .I interval | |
284 | of 0 means to use the default interval. The specified interval must | |
285 | be less than 300 seconds. Requires that the | |
286 | .B mmp | |
287 | feature be enabled. | |
288 | .TP | |
0c17cb25 | 289 | .BI stride= stride-size |
c6a44136 | 290 | Configure the filesystem for a RAID array with |
0c17cb25 TT |
291 | .I stride-size |
292 | filesystem blocks. This is the number of blocks read or written to disk | |
98794d0e | 293 | before moving to the next disk, which is sometimes referred to as the |
2ac7f066 TT |
294 | .I chunk size. |
295 | This mostly affects placement of filesystem metadata like bitmaps at | |
a4396e9d | 296 | .B mke2fs |
98794d0e BS |
297 | time to avoid placing them on a single disk, which can hurt performance. |
298 | It may also be used by the block allocator. | |
0c17cb25 | 299 | .TP |
d4c0d8e5 | 300 | .BI stripe_width= stripe-width |
0c17cb25 TT |
301 | Configure the filesystem for a RAID array with |
302 | .I stripe-width | |
98794d0e | 303 | filesystem blocks per stripe. This is typically stride-size * N, where |
2ac7f066 | 304 | N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one |
98794d0e | 305 | parity disk, so N will be the number of disks in the array minus 1). |
0c17cb25 TT |
306 | This allows the block allocator to prevent read-modify-write of the |
307 | parity in a RAID stripe if possible when the data is written. | |
c6a44136 | 308 | .TP |
88ee023b TT |
309 | .BI offset= offset |
310 | Create the filesystem at an offset from the beginning of the device or | |
311 | file. This can be useful when creating disk images for virtual machines. | |
312 | .TP | |
c6a44136 TT |
313 | .BI resize= max-online-resize |
314 | Reserve enough space so that the block group descriptor table can grow | |
98794d0e BS |
315 | to support a filesystem that has |
316 | .I max-online-resize | |
317 | blocks. | |
6cb27404 | 318 | .TP |
3b4a66cf | 319 | .B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] |
a4396e9d | 320 | If enabled and the uninit_bg feature is enabled, the inode table will |
98794d0e | 321 | not be fully initialized by |
a4396e9d TT |
322 | .BR mke2fs . |
323 | This speeds up filesystem | |
98794d0e | 324 | initialization noticeably, but it requires the kernel to finish |
a4396e9d | 325 | initializing the filesystem in the background when the filesystem is |
43781b94 | 326 | first mounted. If the option value is omitted, it defaults to 1 to |
6c54689f AD |
327 | enable lazy inode table zeroing. |
328 | .TP | |
329 | .B lazy_journal_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] | |
330 | If enabled, the journal inode will not be fully zeroed out by | |
331 | .BR mke2fs . | |
332 | This speeds up filesystem initialization noticeably, but carries some | |
333 | small risk if the system crashes before the journal has been overwritten | |
334 | entirely one time. If the option value is omitted, it defaults to 1 to | |
335 | enable lazy journal inode zeroing. | |
a4396e9d | 336 | .TP |
65c6c3e0 TT |
337 | .BI num_backup_sb= <0|1|2> |
338 | If the | |
339 | .B sparse_super2 | |
340 | file system feature is enabled this option controls whether there will | |
341 | be 0, 1, or 2 backup superblocks created in the file system. | |
342 | .TP | |
3c6e91c5 TT |
343 | .B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR] |
344 | Place the allocation bitmaps and the inode table at the beginning of the | |
345 | disk. This option requires that the flex_bg file system feature to be | |
346 | enabled in order for it to have effect, and will also create the journal | |
347 | at the beginning of the file system. This option is useful for flash | |
348 | devices that use SLC flash at the beginning of the disk. | |
349 | It also maximizes the range of contiguous data blocks, which | |
350 | can be useful for certain specialized use cases, such as supported | |
351 | Shingled Drives. | |
352 | .TP | |
dc9cc700 AD |
353 | .BI root_owner [=uid:gid] |
354 | Specify the numeric user and group ID of the root directory. If no UID:GID | |
355 | is specified, use the user and group ID of the user running \fBmke2fs\fR. | |
356 | In \fBmke2fs\fR 1.42 and earlier the UID and GID of the root directory were | |
357 | set by default to the UID and GID of the user running the mke2fs command. | |
358 | The \fBroot_owner=\fR option allows explicitly specifying these values, | |
359 | and avoid side-effects for users that do not expect the contents of the | |
360 | filesystem to change based on the user running \fBmke2fs\fR. | |
361 | .TP | |
6cb27404 TT |
362 | .B test_fs |
363 | Set a flag in the filesystem superblock indicating that it may be | |
364 | mounted using experimental kernel code, such as the ext4dev filesystem. | |
0bc85dfb LC |
365 | .TP |
366 | .BI discard | |
367 | Attempt to discard blocks at mkfs time (discarding blocks initially is useful | |
368 | on solid state devices and sparse / thin-provisioned storage). When the device | |
369 | advertises that discard also zeroes data (any subsequent read after the discard | |
370 | and before write returns zero), then mark all not-yet-zeroed inode tables as | |
371 | zeroed. This significantly speeds up filesystem initialization. This is set | |
372 | as default. | |
373 | .TP | |
374 | .BI nodiscard | |
855a77a1 | 375 | Do not attempt to discard blocks at mkfs time. |
9e8fcd6e TT |
376 | .TP |
377 | .BI quotatype | |
bc8f1ae5 TT |
378 | Specify the which quota types (usrquota, grpquota, prjquota) which |
379 | should be enabled in the created file system. The argument of this | |
380 | extended option should be a colon separated list. This option has | |
381 | effect only if the | |
9e8fcd6e | 382 | .B quota |
bc8f1ae5 TT |
383 | feature is set. The default quota types to be initialized if this |
384 | option is not specified is both user and group quotas. If the project | |
385 | feature is enabled that project quotas will be initialized as well. | |
c6a44136 TT |
386 | .RE |
387 | .TP | |
48015ced | 388 | .B \-F |
98794d0e | 389 | Force |
48015ced | 390 | .B mke2fs |
c16e610c AD |
391 | to create a filesystem, even if the specified device is not a partition |
392 | on a block special device, or if other parameters do not make sense. | |
98794d0e | 393 | In order to force |
c16e610c | 394 | .B mke2fs |
98794d0e | 395 | to create a filesystem even if the filesystem appears to be in use |
c16e610c AD |
396 | or is mounted (a truly dangerous thing to do), this option must be |
397 | specified twice. | |
48015ced | 398 | .TP |
5e05541a TT |
399 | .BI \-g " blocks-per-group" |
400 | Specify the number of blocks in a block group. There is generally no | |
98794d0e | 401 | reason for the user to ever set this parameter, as the default is optimal |
5e05541a TT |
402 | for the filesystem. (For administrators who are creating |
403 | filesystems on RAID arrays, it is preferable to use the | |
404 | .I stride | |
405 | RAID parameter as part of the | |
e28a1bca | 406 | .B \-E |
98794d0e | 407 | option rather than manipulating the number of blocks per group.) |
5e05541a | 408 | This option is generally used by developers who |
98794d0e | 409 | are developing test cases. |
0f680ee8 ZL |
410 | .IP |
411 | If the bigalloc feature is enabled, the | |
412 | .B \-g | |
413 | option will specify the number of clusters in a block group. | |
5e05541a | 414 | .TP |
9ba40002 | 415 | .BI \-G " number-of-groups" |
98794d0e | 416 | Specify the number of block groups that will be packed together to |
7a9f055f TT |
417 | create a larger virtual block group (or "flex_bg group") in an |
418 | ext4 filesystem. This improves meta-data locality and performance | |
419 | on meta-data heavy workloads. The number of groups must be a power | |
d04ad325 | 420 | of 2 and may only be specified if the |
7a9f055f TT |
421 | .B flex_bg |
422 | filesystem feature is enabled. | |
9ba40002 | 423 | .TP |
caf8ce4c | 424 | .BI \-i " bytes-per-inode" |
98794d0e | 425 | Specify the bytes/inode ratio. |
3839e657 TT |
426 | .B mke2fs |
427 | creates an inode for every | |
428 | .I bytes-per-inode | |
98794d0e | 429 | bytes of space on the disk. The larger the |
caf8ce4c | 430 | .I bytes-per-inode |
48015ced | 431 | ratio, the fewer inodes will be created. This value generally shouldn't |
98794d0e BS |
432 | be smaller than the blocksize of the filesystem, since in that case more |
433 | inodes would be made than can ever be used. Be warned that it is not | |
e2883e27 PS |
434 | possible to change this ratio on a filesystem after it is created, so be |
435 | careful deciding the correct value for this parameter. Note that resizing | |
ce20096f | 436 | a filesystem changes the number of inodes to maintain this ratio. |
067911ae AD |
437 | .TP |
438 | .BI \-I " inode-size" | |
98794d0e | 439 | Specify the size of each inode in bytes. |
886056bd | 440 | The |
067911ae | 441 | .I inode-size |
98794d0e | 442 | value must be a power of 2 larger or equal to 128. The larger the |
067911ae AD |
443 | .I inode-size |
444 | the more space the inode table will consume, and this reduces the usable | |
98794d0e | 445 | space in the filesystem and can also negatively impact performance. |
886056bd TT |
446 | It is not |
447 | possible to change this value after the filesystem is created. | |
448 | .IP | |
449 | In kernels after 2.6.10 and some | |
450 | earlier vendor kernels it is possible to utilize inodes larger than | |
451 | 128 bytes to store | |
452 | extended attributes for improved performance. | |
e67670c3 | 453 | Extended attributes |
067911ae | 454 | stored in large inodes are not visible with older kernels, and such |
d04ad325 | 455 | filesystems will not be mountable with 2.4 kernels at all. |
886056bd TT |
456 | .IP |
457 | The default inode size is controlled by the | |
458 | .BR mke2fs.conf (5) | |
459 | file. In the | |
460 | .B mke2fs.conf | |
461 | file shipped with e2fsprogs, the default inode size is 256 bytes for | |
462 | most file systems, except for small file systems where the inode size | |
463 | will be 128 bytes. | |
98794d0e | 464 | .TP |
48015ced TT |
465 | .B \-j |
466 | Create the filesystem with an ext3 journal. If the | |
dc2ec525 | 467 | .B \-J |
48015ced | 468 | option is not specified, the default journal parameters will be used to |
98794d0e | 469 | create an appropriately sized journal (given the size of the filesystem) |
48015ced TT |
470 | stored within the filesystem. Note that you must be using a kernel |
471 | which has ext3 support in order to actually make use of the journal. | |
dc2ec525 | 472 | .TP |
48015ced | 473 | .BI \-J " journal-options" |
dc2ec525 | 474 | Create the ext3 journal using options specified on the command-line. |
8ddaa66b TT |
475 | Journal options are comma |
476 | separated, and may take an argument using the equals ('=') sign. | |
48015ced TT |
477 | The following journal options are supported: |
478 | .RS 1.2i | |
dc2ec525 | 479 | .TP |
48015ced | 480 | .BI size= journal-size |
f0865ce4 | 481 | Create an internal journal (i.e., stored inside the filesystem) of size |
98794d0e | 482 | .I journal-size |
8d641749 | 483 | megabytes. |
98794d0e BS |
484 | The size of the journal must be at least 1024 filesystem blocks |
485 | (i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.) | |
57cb2716 SP |
486 | and may be no more than 10,240,000 filesystem blocks or half the total |
487 | file system size (whichever is smaller) | |
b818205f TT |
488 | .TP |
489 | .BI location =journal-location | |
490 | Specify the location of the journal. The argument | |
491 | .I journal-location | |
492 | can either be specified as a block number, or if the number has a units | |
493 | suffix (e.g., 'M', 'G', etc.) interpret it as the offset from the | |
494 | beginning of the file system. | |
48015ced TT |
495 | @JDEV@.TP |
496 | @JDEV@.BI device= external-journal | |
8d641749 TT |
497 | @JDEV@Attach the filesystem to the journal block device located on |
498 | @JDEV@.IR external-journal . | |
499 | @JDEV@The external | |
500 | @JDEV@journal must already have been created using the command | |
501 | @JDEV@.IP | |
2d15576d AD |
502 | @JDEV@.B mke2fs -O journal_dev |
503 | @JDEV@.I external-journal | |
8d641749 TT |
504 | @JDEV@.IP |
505 | @JDEV@Note that | |
506 | @JDEV@.I external-journal | |
507 | @JDEV@must have been created with the | |
508 | @JDEV@same block size as the new filesystem. | |
3024d887 TT |
509 | @JDEV@In addition, while there is support for attaching |
510 | @JDEV@multiple filesystems to a single external journal, | |
98794d0e | 511 | @JDEV@the Linux kernel and |
3024d887 TT |
512 | @JDEV@.BR e2fsck (8) |
513 | @JDEV@do not currently support shared external journals yet. | |
2d15576d AD |
514 | @JDEV@.IP |
515 | @JDEV@Instead of specifying a device name directly, | |
516 | @JDEV@.I external-journal | |
517 | @JDEV@can also be specified by either | |
518 | @JDEV@.BI LABEL= label | |
519 | @JDEV@or | |
520 | @JDEV@.BI UUID= UUID | |
521 | @JDEV@to locate the external journal by either the volume label or UUID | |
522 | @JDEV@stored in the ext2 superblock at the start of the journal. Use | |
523 | @JDEV@.BR dumpe2fs (8) | |
524 | @JDEV@to display a journal device's volume label and UUID. See also the | |
525 | @JDEV@.B -L | |
526 | @JDEV@option of | |
527 | @JDEV@.BR tune2fs (8). | |
8d641749 TT |
528 | .RE |
529 | @JDEV@.IP | |
48015ced TT |
530 | @JDEV@Only one of the |
531 | @JDEV@.BR size " or " device | |
532 | @JDEV@options can be given for a filesystem. | |
48015ced TT |
533 | .TP |
534 | .BI \-l " filename" | |
535 | Read the bad blocks list from | |
98794d0e | 536 | .IR filename . |
3ed57c27 | 537 | Note that the block numbers in the bad block list must be generated |
98794d0e BS |
538 | using the same block size as used by |
539 | .BR mke2fs . | |
540 | As a result, the | |
3ed57c27 | 541 | .B \-c |
98794d0e | 542 | option to |
3ed57c27 TT |
543 | .B mke2fs |
544 | is a much simpler and less error-prone method of checking a disk for bad | |
98794d0e | 545 | blocks before formatting it, as |
3ed57c27 TT |
546 | .B mke2fs |
547 | will automatically pass the correct parameters to the | |
548 | .B badblocks | |
549 | program. | |
48015ced | 550 | .TP |
6a7075df TT |
551 | .BI \-L " new-volume-label" |
552 | Set the volume label for the filesystem to | |
553 | .IR new-volume-label . | |
554 | The maximum length of the | |
555 | volume label is 16 bytes. | |
48015ced TT |
556 | .TP |
557 | .BI \-m " reserved-blocks-percentage" | |
98794d0e | 558 | Specify the percentage of the filesystem blocks reserved for |
029de632 | 559 | the super-user. This avoids fragmentation, and allows root-owned |
98794d0e | 560 | daemons, such as |
029de632 | 561 | .BR syslogd (8), |
98794d0e BS |
562 | to continue to function correctly after non-privileged processes are |
563 | prevented from writing to the filesystem. The default percentage | |
029de632 | 564 | is 5%. |
dc2ec525 | 565 | .TP |
98794d0e BS |
566 | .BI \-M " last-mounted-directory" |
567 | Set the last mounted directory for the filesystem. This might be useful | |
568 | for the sake of utilities that key off of the last mounted directory to | |
bcf5aea2 | 569 | determine where the filesystem should be mounted. |
85ef4ae8 | 570 | .TP |
caf8ce4c | 571 | .B \-n |
98794d0e BS |
572 | Causes |
573 | .B mke2fs | |
574 | to not actually create a filesystem, but display what it | |
1f22ce34 TT |
575 | would do if it were to create a filesystem. This can be used to |
576 | determine the location of the backup superblocks for a particular | |
98794d0e BS |
577 | filesystem, so long as the |
578 | .B mke2fs | |
579 | parameters that were passed when the | |
1f22ce34 | 580 | filesystem was originally created are used again. (With the |
98794d0e | 581 | .B \-n |
1f22ce34 | 582 | option added, of course!) |
2740156b | 583 | .TP |
caf8ce4c | 584 | .BI \-N " number-of-inodes" |
98794d0e BS |
585 | Overrides the default calculation of the number of inodes that should be |
586 | reserved for the filesystem (which is based on the number of blocks and | |
587 | the | |
caf8ce4c | 588 | .I bytes-per-inode |
98794d0e | 589 | ratio). This allows the user to specify the number |
5515e6b4 TT |
590 | of desired inodes directly. |
591 | .TP | |
48015ced | 592 | .BI \-o " creator-os" |
98794d0e BS |
593 | Overrides the default value of the "creator operating system" field of the |
594 | filesystem. The creator field is set by default to the name of the OS the | |
583ccdc3 | 595 | .B mke2fs |
98794d0e | 596 | executable was compiled for. |
1e3472c5 | 597 | .TP |
5c4c3876 | 598 | .B "\-O \fR[^]\fIfeature\fR[,...]" |
98794d0e BS |
599 | Create a filesystem with the given features (filesystem options), |
600 | overriding the default filesystem options. The features that are | |
9dc6ad1e TT |
601 | enabled by default are specified by the |
602 | .I base_features | |
603 | relation, either in the | |
98794d0e | 604 | .I [defaults] |
9dc6ad1e TT |
605 | section in the |
606 | .B /etc/mke2fs.conf | |
3d43836f | 607 | configuration file, |
98794d0e | 608 | or in the |
9dc6ad1e | 609 | .I [fs_types] |
98794d0e | 610 | subsections for the usage types as specified by the |
a26ba650 | 611 | .B \-T |
3d43836f TT |
612 | option, further modified by the |
613 | .I features | |
614 | relation found in the | |
98794d0e BS |
615 | .I [fs_types] |
616 | subsections for the filesystem and usage types. See the | |
3d43836f TT |
617 | .BR mke2fs.conf (5) |
618 | manual page for more details. | |
619 | The filesystem type-specific configuration setting found in the | |
9dc6ad1e TT |
620 | .I [fs_types] |
621 | section will override the global default found in | |
98794d0e | 622 | .IR [defaults] . |
48015ced | 623 | .sp |
98794d0e BS |
624 | The filesystem feature set will be further edited |
625 | using either the feature set specified by this option, | |
626 | or if this option is not given, by the | |
9dc6ad1e | 627 | .I default_features |
98794d0e BS |
628 | relation for the filesystem type being created, or in the |
629 | .I [defaults] | |
9dc6ad1e TT |
630 | section of the configuration file. |
631 | .sp | |
632 | The filesystem feature set is comprised of a list of features, separated | |
633 | by commas, that are to be enabled. To disable a feature, simply | |
5c4c3876 | 634 | prefix the feature name with a caret ('^') character. |
3c22bf7e | 635 | Features with dependencies will not be removed successfully. |
4727c67d | 636 | The pseudo-filesystem feature "none" will clear all filesystem features. |
4727c67d | 637 | .TP |
3c22bf7e TT |
638 | For more information about the features which can be set, please see |
639 | the manual page | |
640 | .BR ext4 (5). | |
1e3472c5 | 641 | .TP |
8d641749 | 642 | .B \-q |
98794d0e | 643 | Quiet execution. Useful if |
8d641749 TT |
644 | .B mke2fs |
645 | is run in a script. | |
646 | .TP | |
48015ced | 647 | .BI \-r " revision" |
a29f4d30 | 648 | Set the filesystem revision for the new filesystem. Note that 1.2 |
98794d0e | 649 | kernels only support revision 0 filesystems. The default is to |
48015ced | 650 | create revision 1 filesystems. |
a29f4d30 | 651 | .TP |
caf8ce4c | 652 | .B \-S |
a6eeac1c AD |
653 | Write superblock and group descriptors only. This is an extreme |
654 | measure to be taken only in the very unlikely case that all of | |
f3db3566 | 655 | the superblock and backup superblocks are corrupted, and a last-ditch |
a6eeac1c | 656 | recovery method is desired by experienced users. It causes |
583ccdc3 | 657 | .B mke2fs |
a6eeac1c AD |
658 | to reinitialize the superblock and group descriptors, while not |
659 | touching the inode table and the block and inode bitmaps. The | |
f3db3566 TT |
660 | .B e2fsck |
661 | program should be run immediately after this option is used, and there | |
a6eeac1c AD |
662 | is no guarantee that any data will be salvageable. Due to the wide |
663 | variety of possible options to | |
664 | .BR mke2fs | |
a7dc56f4 | 665 | that affect the on-disk layout, it is critical to specify exactly |
a6eeac1c AD |
666 | the same format options, such as blocksize, fs-type, feature flags, and |
667 | other tunables when using this option, or the filesystem will be further | |
668 | corrupted. In some cases, such as filesystems that have been resized, | |
669 | or have had features enabled after format time, it is impossible to | |
a7dc56f4 | 670 | overwrite all of the superblocks correctly, and at least some filesystem |
a6eeac1c AD |
671 | corruption will occur. It is best to run this on a full copy of the |
672 | filesystem so other options can be tried if this doesn't work. | |
8d641749 TT |
673 | .\" .TP |
674 | .\" .BI \-t " test" | |
675 | .\" Check the device for bad blocks before creating the file system | |
676 | .\" using the specified test. | |
818180cd | 677 | .TP |
3d43836f | 678 | .BI \-t " fs-type" |
4727c67d UC |
679 | Specify the filesystem type (i.e., ext2, ext3, ext4, etc.) that is |
680 | to be created. | |
98794d0e BS |
681 | If this option is not specified, |
682 | .B mke2fs | |
683 | will pick a default either via how | |
684 | the command was run (for example, using a name of the form mkfs.ext2, | |
3d43836f | 685 | mkfs.ext3, etc.) or via a default as defined by the |
626a2e74 | 686 | .B /etc/mke2fs.conf |
08c8b1ab TT |
687 | file. This option controls which filesystem options are used by |
688 | default, based on the | |
689 | .B fstypes | |
690 | configuration stanza in | |
626a2e74 | 691 | .BR /etc/mke2fs.conf . |
08c8b1ab TT |
692 | .sp |
693 | If the | |
694 | .B \-O | |
695 | option is used to explicitly add or remove filesystem options that | |
696 | should be set in the newly created filesystem, the | |
697 | resulting filesystem may not be supported by the requested | |
698 | .IR fs-type . | |
b7150807 | 699 | (e.g., "\fBmke2fs \-t ext3 \-O extent /dev/sdXX\fR" will create a |
08c8b1ab | 700 | filesystem that is not supported by the ext3 implementation as found in |
93aa0246 | 701 | the Linux kernel; and "\fBmke2fs \-t ext3 \-O ^has_journal /dev/hdXX\fR" |
08c8b1ab TT |
702 | will create a filesystem that does not have a journal and hence will not |
703 | be supported by the ext3 filesystem code in the Linux kernel.) | |
3d43836f TT |
704 | .TP |
705 | .BI \-T " usage-type[,...]" | |
98794d0e BS |
706 | Specify how the filesystem is going to be used, so that |
707 | .B mke2fs | |
3d43836f TT |
708 | can choose optimal filesystem parameters for that use. The usage |
709 | types that are supported are defined in the configuration file | |
626a2e74 | 710 | .BR /etc/mke2fs.conf . |
3d43836f TT |
711 | The user may specify one or more usage types |
712 | using a comma separated list. | |
713 | .sp | |
714 | If this option is is not specified, | |
715 | .B mke2fs | |
716 | will pick a single default usage type based on the size of the filesystem to | |
0745e787 | 717 | be created. If the filesystem size is less than 3 megabytes, |
a4396e9d | 718 | .B mke2fs |
3d43836f TT |
719 | will use the filesystem type |
720 | .IR floppy . | |
0745e787 | 721 | If the filesystem size is greater than or equal to 3 but less than |
3d43836f TT |
722 | 512 megabytes, |
723 | .BR mke2fs (8) | |
9a2767ff | 724 | will use the filesystem type |
3d43836f | 725 | .IR small . |
9a2767ff NK |
726 | If the filesystem size is greater than or equal to 4 terabytes but less than |
727 | 16 terabytes, | |
728 | .BR mke2fs (8) | |
729 | will use the filesystem type | |
730 | .IR big . | |
731 | If the filesystem size is greater than or equal to 16 terabytes, | |
732 | .BR mke2fs (8) | |
733 | will use the filesystem type | |
734 | .IR huge . | |
3d43836f TT |
735 | Otherwise, |
736 | .BR mke2fs (8) | |
737 | will use the default filesystem type | |
738 | .IR default . | |
48015ced | 739 | .TP |
b0afdda1 | 740 | .BI \-U " UUID" |
665ebf37 DD |
741 | Set the universally unique identifier (UUID) of the filesystem to |
742 | .IR UUID . | |
743 | The format of the UUID is a series of hex digits separated by hyphens, | |
744 | like this: | |
745 | "c1b9d5a2-f162-11cf-9ece-0020afc76f16". | |
746 | The | |
747 | .I UUID | |
748 | parameter may also be one of the following: | |
749 | .RS 1.2i | |
750 | .TP | |
751 | .I clear | |
752 | clear the filesystem UUID | |
753 | .TP | |
754 | .I random | |
755 | generate a new randomly-generated UUID | |
756 | .TP | |
757 | .I time | |
758 | generate a new time-based UUID | |
759 | .RE | |
b0afdda1 | 760 | .TP |
48015ced TT |
761 | .B \-v |
762 | Verbose execution. | |
50787ea2 | 763 | .TP |
caf8ce4c | 764 | .B \-V |
98794d0e | 765 | Print the version number of |
818180cd TT |
766 | .B mke2fs |
767 | and exit. | |
2d291b3c DW |
768 | .TP |
769 | .BI \-z " undo_file" | |
770 | Before overwriting a file system block, write the old contents of the block to | |
771 | an undo file. This undo file can be used with e2undo(8) to restore the old | |
772 | contents of the file system should something go wrong. If the empty string is | |
773 | passed as the undo_file argument, the undo file will be written to a file named | |
774 | mke2fs-\fIdevice\fR.e2undo in the directory specified via the | |
775 | \fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive | |
776 | in the configuration file. | |
777 | ||
778 | WARNING: The undo file cannot be used to recover from a power or system crash. | |
5182ad4c NK |
779 | .SH ENVIRONMENT |
780 | .TP | |
781 | .BI MKE2FS_SYNC | |
782 | If set to non-zero integer value, its value is used to determine how often | |
783 | .BR sync (2) | |
784 | is called during inode table initialization. | |
785 | .TP | |
786 | .BI MKE2FS_CONFIG | |
787 | Determines the location of the configuration file (see | |
788 | .BR mke2fs.conf (5)). | |
789 | .TP | |
790 | .BI MKE2FS_FIRST_META_BG | |
791 | If set to non-zero integer value, its value is used to determine first meta | |
792 | block group. This is mostly for debugging purposes. | |
793 | .TP | |
794 | .BI MKE2FS_DEVICE_SECTSIZE | |
795 | If set to non-zero integer value, its value is used to determine physical | |
796 | sector size of the | |
797 | .IR device . | |
798 | .TP | |
799 | .BI MKE2FS_SKIP_CHECK_MSG | |
800 | If set, do not show the message of filesystem automatic check caused by | |
801 | mount count or check interval. | |
3839e657 TT |
802 | .SH AUTHOR |
803 | This version of | |
804 | .B mke2fs | |
a418d3ad | 805 | has been written by Theodore Ts'o <tytso@mit.edu>. |
3839e657 TT |
806 | .SH AVAILABILITY |
807 | .B mke2fs | |
98794d0e | 808 | is part of the e2fsprogs package and is available from |
348e43dc | 809 | http://e2fsprogs.sourceforge.net. |
3839e657 | 810 | .SH SEE ALSO |
9dc6ad1e | 811 | .BR mke2fs.conf (5), |
e72a9ba3 | 812 | .BR badblocks (8), |
3839e657 TT |
813 | .BR dumpe2fs (8), |
814 | .BR e2fsck (8), | |
3c22bf7e TT |
815 | .BR tune2fs (8), |
816 | .BR ext4 (5) |