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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 | [ | |
75dd3c47 TN |
21 | .B \-C |
22 | .I cluster-size | |
23 | ] | |
24 | [ | |
4407ea3b DW |
25 | .B \-d |
26 | .I root-directory | |
27 | ] | |
28 | [ | |
37c8db7b TT |
29 | .B \-D |
30 | ] | |
31 | [ | |
5e05541a TT |
32 | .B \-g |
33 | .I blocks-per-group | |
34 | ] | |
35 | [ | |
9ba40002 TT |
36 | .B \-G |
37 | .I number-of-groups | |
38 | ] | |
39 | [ | |
3839e657 | 40 | .B \-i |
1e3472c5 | 41 | .I bytes-per-inode |
3839e657 TT |
42 | ] |
43 | [ | |
067911ae AD |
44 | .B \-I |
45 | .I inode-size | |
46 | ] | |
47 | [ | |
85ef4ae8 | 48 | .B \-j |
dc2ec525 TT |
49 | ] |
50 | [ | |
51 | .B \-J | |
8ddaa66b | 52 | .I journal-options |
85ef4ae8 TT |
53 | ] |
54 | [ | |
5515e6b4 TT |
55 | .B \-N |
56 | .I number-of-inodes | |
57 | ] | |
58 | [ | |
a26ba650 | 59 | .B \-n |
2740156b TT |
60 | ] |
61 | [ | |
3839e657 | 62 | .B \-m |
1e3472c5 TT |
63 | .I reserved-blocks-percentage |
64 | ] | |
65 | [ | |
66 | .B \-o | |
67 | .I creator-os | |
3839e657 TT |
68 | ] |
69 | [ | |
98794d0e | 70 | .B \-O |
5c4c3876 | 71 | [^]\fIfeature\fR[,...] |
896938d5 TT |
72 | ] |
73 | [ | |
f3db3566 TT |
74 | .B \-q |
75 | ] | |
76 | [ | |
caf8ce4c TT |
77 | .B \-r |
78 | .I fs-revision-level | |
a29f4d30 TT |
79 | ] |
80 | [ | |
c6a44136 TT |
81 | .B \-E |
82 | .I extended-options | |
521e3685 TT |
83 | ] |
84 | [ | |
3839e657 TT |
85 | .B \-v |
86 | ] | |
f3db3566 | 87 | [ |
74becf3c TT |
88 | .B \-F |
89 | ] | |
90 | [ | |
1e3472c5 TT |
91 | .B \-L |
92 | .I volume-label | |
93 | ] | |
94 | [ | |
95 | .B \-M | |
96 | .I last-mounted-directory | |
97 | ] | |
98 | [ | |
f3db3566 TT |
99 | .B \-S |
100 | ] | |
818180cd | 101 | [ |
3d43836f TT |
102 | .B \-t |
103 | .I fs-type | |
104 | ] | |
105 | [ | |
50787ea2 | 106 | .B \-T |
3d43836f | 107 | .I usage-type |
50787ea2 TT |
108 | ] |
109 | [ | |
b0afdda1 TT |
110 | .B \-U |
111 | .I UUID | |
112 | ] | |
113 | [ | |
818180cd TT |
114 | .B \-V |
115 | ] | |
cd32129d DW |
116 | [ |
117 | .B \-e | |
118 | .I errors-behavior | |
119 | ] | |
2d291b3c DW |
120 | [ |
121 | .B \-z | |
122 | .I undo_file | |
123 | ] | |
1e3472c5 | 124 | .I device |
3839e657 | 125 | [ |
9ac2930c | 126 | .I fs-size |
3839e657 | 127 | ] |
48015ced | 128 | @JDEV@.sp |
8d641749 | 129 | @JDEV@.B "mke2fs \-O journal_dev" |
48015ced TT |
130 | @JDEV@[ |
131 | @JDEV@.B \-b | |
132 | @JDEV@.I block-size | |
133 | @JDEV@] | |
8d641749 | 134 | .\" No external-journal specific journal options yet (size is ignored) |
48015ced TT |
135 | .\" @JDEV@[ |
136 | .\" @JDEV@.B \-J | |
137 | .\" @JDEV@.I journal-options | |
138 | .\" @JDEV@] | |
139 | @JDEV@[ | |
140 | @JDEV@.B \-L | |
141 | @JDEV@.I volume-label | |
142 | @JDEV@] | |
143 | @JDEV@[ | |
144 | @JDEV@.B \-n | |
145 | @JDEV@] | |
146 | @JDEV@[ | |
147 | @JDEV@.B \-q | |
148 | @JDEV@] | |
149 | @JDEV@[ | |
150 | @JDEV@.B \-v | |
151 | @JDEV@] | |
8d641749 | 152 | @JDEV@.I external-journal |
2d15576d | 153 | @JDEV@[ |
9ac2930c | 154 | @JDEV@.I fs-size |
2d15576d | 155 | @JDEV@] |
3839e657 TT |
156 | .SH DESCRIPTION |
157 | .B mke2fs | |
4f858546 | 158 | is used to create an ext2, ext3, or ext4 filesystem, usually in a disk |
9ac2930c TT |
159 | partition (or file) named by |
160 | .IR device . | |
161 | .PP | |
162 | The file system size is specified by | |
163 | .IR fs-size . | |
164 | If | |
165 | .I fs-size | |
166 | does not have a suffix, it is interpreted as power-of-two kilobytes, | |
167 | unless the | |
168 | .B \-b | |
169 | .I blocksize | |
170 | option is specified, in which case | |
171 | .I fs-size | |
172 | is interpreted as the number of | |
173 | .I blocksize | |
174 | blocks. If the fs-size is suffixed by 'k', 'm', 'g', 't' | |
175 | (either upper-case or lower-case), then it is interpreted in | |
176 | power-of-two kilobytes, megabytes, gigabytes, terabytes, etc. | |
177 | If | |
178 | .I fs-size | |
179 | is omitted, | |
3839e657 | 180 | .B mke2fs |
9ac2930c TT |
181 | will create the file system based on the device size. |
182 | .PP | |
183 | If | |
184 | .B mke2fs | |
185 | is run as | |
186 | .B mkfs.XXX | |
187 | (i.e., | |
188 | .BR mkfs.ext2 , | |
189 | .BR mkfs.ext3 , | |
190 | or | |
191 | .BR mkfs.ext4 ) | |
192 | the option | |
193 | .B \-t | |
194 | .I XXX | |
195 | is implied; so | |
0072f8de | 196 | .B mkfs.ext3 |
9ac2930c TT |
197 | will create a file system for use with ext3, |
198 | .B mkfs.ext4 | |
199 | will create a file system for use with ext4, and so on. | |
de7a86e2 TT |
200 | .PP |
201 | The defaults of the parameters for the newly created filesystem, if not | |
202 | overridden by the options listed below, are controlled by the | |
203 | .B /etc/mke2fs.conf | |
204 | configuration file. See the | |
205 | .BR mke2fs.conf (5) | |
206 | manual page for more details. | |
3839e657 TT |
207 | .SH OPTIONS |
208 | .TP | |
caf8ce4c | 209 | .BI \-b " block-size" |
98794d0e | 210 | Specify the size of blocks in bytes. Valid block-size values are 1024, |
06968e7e | 211 | 2048 and 4096 bytes per block. If omitted, |
98794d0e | 212 | block-size is heuristically determined by the filesystem size and |
c5290fae | 213 | the expected usage of the filesystem (see the |
06968e7e | 214 | .B \-T |
98794d0e | 215 | option). If |
c5290fae | 216 | .I block-size |
eddf36ba | 217 | is preceded by a negative sign ('-'), then |
c6a44136 TT |
218 | .B mke2fs |
219 | will use heuristics to determine the | |
c5290fae | 220 | appropriate block size, with the constraint that the block size will be |
98794d0e | 221 | at least |
c5290fae TT |
222 | .I block-size |
223 | bytes. This is useful for certain hardware devices which require that | |
224 | the blocksize be a multiple of 2k. | |
3839e657 | 225 | .TP |
caf8ce4c | 226 | .B \-c |
3ed57c27 | 227 | Check the device for bad blocks before creating the file system. If |
98794d0e | 228 | this option is specified twice, then a slower read-write |
3ed57c27 | 229 | test is used instead of a fast read-only test. |
3839e657 | 230 | .TP |
0f680ee8 ZL |
231 | .B \-C " cluster-size" |
232 | Specify the size of cluster in bytes for filesystems using the bigalloc | |
233 | feature. Valid cluster-size values are from 2048 to 256M bytes per | |
9518b297 TT |
234 | cluster. This can only be specified if the bigalloc feature is |
235 | enabled. (See the | |
236 | .B ext4 (5) | |
237 | man page for more details about bigalloc.) The default cluster size if | |
238 | bigalloc is enabled is 16 times the block size. | |
0f680ee8 | 239 | .TP |
4407ea3b DW |
240 | .BI \-d " root-directory" |
241 | Copy the contents of the given directory into the root directory of the | |
242 | filesystem. | |
243 | .TP | |
37c8db7b TT |
244 | .B \-D |
245 | Use direct I/O when writing to the disk. This avoids mke2fs dirtying a | |
246 | lot of buffer cache memory, which may impact other applications running | |
247 | on a busy server. This option will cause mke2fs to run much more | |
248 | slowly, however, so there is a tradeoff to using direct I/O. | |
249 | .TP | |
cd32129d DW |
250 | .BI \-e " error-behavior" |
251 | Change the behavior of the kernel code when errors are detected. | |
252 | In all cases, a filesystem error will cause | |
253 | .BR e2fsck (8) | |
254 | to check the filesystem on the next boot. | |
255 | .I error-behavior | |
256 | can be one of the following: | |
257 | .RS 1.2i | |
258 | .TP 1.2i | |
259 | .B continue | |
260 | Continue normal execution. | |
261 | .TP | |
262 | .B remount-ro | |
263 | Remount filesystem read-only. | |
264 | .TP | |
265 | .B panic | |
266 | Cause a kernel panic. | |
267 | .RE | |
268 | .TP | |
c6a44136 TT |
269 | .BI \-E " extended-options" |
270 | Set extended options for the filesystem. Extended options are comma | |
271 | separated, and may take an argument using the equals ('=') sign. The | |
a26ba650 | 272 | .B \-E |
98794d0e | 273 | option used to be |
a26ba650 | 274 | .B \-R |
98794d0e | 275 | in earlier versions of |
c6a44136 | 276 | .BR mke2fs . |
98794d0e | 277 | The |
a26ba650 | 278 | .B \-R |
b769aaec AD |
279 | option is still accepted for backwards compatibility, but is deprecated. |
280 | The following extended options are supported: | |
c6a44136 TT |
281 | .RS 1.2i |
282 | .TP | |
0f5eba75 AD |
283 | .BI mmp_update_interval= interval |
284 | Adjust the initial MMP update interval to | |
285 | .I interval | |
286 | seconds. Specifying an | |
287 | .I interval | |
288 | of 0 means to use the default interval. The specified interval must | |
289 | be less than 300 seconds. Requires that the | |
290 | .B mmp | |
291 | feature be enabled. | |
292 | .TP | |
0c17cb25 | 293 | .BI stride= stride-size |
c6a44136 | 294 | Configure the filesystem for a RAID array with |
0c17cb25 TT |
295 | .I stride-size |
296 | filesystem blocks. This is the number of blocks read or written to disk | |
98794d0e | 297 | before moving to the next disk, which is sometimes referred to as the |
2ac7f066 TT |
298 | .I chunk size. |
299 | This mostly affects placement of filesystem metadata like bitmaps at | |
a4396e9d | 300 | .B mke2fs |
98794d0e BS |
301 | time to avoid placing them on a single disk, which can hurt performance. |
302 | It may also be used by the block allocator. | |
0c17cb25 | 303 | .TP |
d4c0d8e5 | 304 | .BI stripe_width= stripe-width |
0c17cb25 TT |
305 | Configure the filesystem for a RAID array with |
306 | .I stripe-width | |
98794d0e | 307 | filesystem blocks per stripe. This is typically stride-size * N, where |
2ac7f066 | 308 | N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one |
98794d0e | 309 | parity disk, so N will be the number of disks in the array minus 1). |
0c17cb25 TT |
310 | This allows the block allocator to prevent read-modify-write of the |
311 | parity in a RAID stripe if possible when the data is written. | |
c6a44136 | 312 | .TP |
88ee023b TT |
313 | .BI offset= offset |
314 | Create the filesystem at an offset from the beginning of the device or | |
315 | file. This can be useful when creating disk images for virtual machines. | |
316 | .TP | |
c6a44136 TT |
317 | .BI resize= max-online-resize |
318 | Reserve enough space so that the block group descriptor table can grow | |
98794d0e BS |
319 | to support a filesystem that has |
320 | .I max-online-resize | |
321 | blocks. | |
6cb27404 | 322 | .TP |
3b4a66cf | 323 | .B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] |
a4396e9d | 324 | If enabled and the uninit_bg feature is enabled, the inode table will |
98794d0e | 325 | not be fully initialized by |
a4396e9d TT |
326 | .BR mke2fs . |
327 | This speeds up filesystem | |
98794d0e | 328 | initialization noticeably, but it requires the kernel to finish |
a4396e9d | 329 | initializing the filesystem in the background when the filesystem is |
43781b94 | 330 | first mounted. If the option value is omitted, it defaults to 1 to |
6c54689f AD |
331 | enable lazy inode table zeroing. |
332 | .TP | |
333 | .B lazy_journal_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] | |
334 | If enabled, the journal inode will not be fully zeroed out by | |
335 | .BR mke2fs . | |
336 | This speeds up filesystem initialization noticeably, but carries some | |
337 | small risk if the system crashes before the journal has been overwritten | |
338 | entirely one time. If the option value is omitted, it defaults to 1 to | |
339 | enable lazy journal inode zeroing. | |
a4396e9d | 340 | .TP |
65c6c3e0 TT |
341 | .BI num_backup_sb= <0|1|2> |
342 | If the | |
343 | .B sparse_super2 | |
344 | file system feature is enabled this option controls whether there will | |
345 | be 0, 1, or 2 backup superblocks created in the file system. | |
346 | .TP | |
3c6e91c5 TT |
347 | .B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR] |
348 | Place the allocation bitmaps and the inode table at the beginning of the | |
349 | disk. This option requires that the flex_bg file system feature to be | |
350 | enabled in order for it to have effect, and will also create the journal | |
351 | at the beginning of the file system. This option is useful for flash | |
352 | devices that use SLC flash at the beginning of the disk. | |
353 | It also maximizes the range of contiguous data blocks, which | |
354 | can be useful for certain specialized use cases, such as supported | |
355 | Shingled Drives. | |
356 | .TP | |
dc9cc700 AD |
357 | .BI root_owner [=uid:gid] |
358 | Specify the numeric user and group ID of the root directory. If no UID:GID | |
359 | is specified, use the user and group ID of the user running \fBmke2fs\fR. | |
360 | In \fBmke2fs\fR 1.42 and earlier the UID and GID of the root directory were | |
361 | set by default to the UID and GID of the user running the mke2fs command. | |
362 | The \fBroot_owner=\fR option allows explicitly specifying these values, | |
363 | and avoid side-effects for users that do not expect the contents of the | |
364 | filesystem to change based on the user running \fBmke2fs\fR. | |
365 | .TP | |
6cb27404 TT |
366 | .B test_fs |
367 | Set a flag in the filesystem superblock indicating that it may be | |
368 | mounted using experimental kernel code, such as the ext4dev filesystem. | |
0bc85dfb LC |
369 | .TP |
370 | .BI discard | |
371 | Attempt to discard blocks at mkfs time (discarding blocks initially is useful | |
372 | on solid state devices and sparse / thin-provisioned storage). When the device | |
373 | advertises that discard also zeroes data (any subsequent read after the discard | |
374 | and before write returns zero), then mark all not-yet-zeroed inode tables as | |
375 | zeroed. This significantly speeds up filesystem initialization. This is set | |
376 | as default. | |
377 | .TP | |
378 | .BI nodiscard | |
855a77a1 | 379 | Do not attempt to discard blocks at mkfs time. |
9e8fcd6e TT |
380 | .TP |
381 | .BI quotatype | |
bc8f1ae5 TT |
382 | Specify the which quota types (usrquota, grpquota, prjquota) which |
383 | should be enabled in the created file system. The argument of this | |
384 | extended option should be a colon separated list. This option has | |
385 | effect only if the | |
9e8fcd6e | 386 | .B quota |
bc8f1ae5 TT |
387 | feature is set. The default quota types to be initialized if this |
388 | option is not specified is both user and group quotas. If the project | |
389 | feature is enabled that project quotas will be initialized as well. | |
c6a44136 TT |
390 | .RE |
391 | .TP | |
48015ced | 392 | .B \-F |
98794d0e | 393 | Force |
48015ced | 394 | .B mke2fs |
c16e610c AD |
395 | to create a filesystem, even if the specified device is not a partition |
396 | on a block special device, or if other parameters do not make sense. | |
98794d0e | 397 | In order to force |
c16e610c | 398 | .B mke2fs |
98794d0e | 399 | to create a filesystem even if the filesystem appears to be in use |
c16e610c AD |
400 | or is mounted (a truly dangerous thing to do), this option must be |
401 | specified twice. | |
48015ced | 402 | .TP |
5e05541a TT |
403 | .BI \-g " blocks-per-group" |
404 | Specify the number of blocks in a block group. There is generally no | |
98794d0e | 405 | reason for the user to ever set this parameter, as the default is optimal |
5e05541a TT |
406 | for the filesystem. (For administrators who are creating |
407 | filesystems on RAID arrays, it is preferable to use the | |
408 | .I stride | |
409 | RAID parameter as part of the | |
e28a1bca | 410 | .B \-E |
98794d0e | 411 | option rather than manipulating the number of blocks per group.) |
5e05541a | 412 | This option is generally used by developers who |
98794d0e | 413 | are developing test cases. |
0f680ee8 ZL |
414 | .IP |
415 | If the bigalloc feature is enabled, the | |
416 | .B \-g | |
417 | option will specify the number of clusters in a block group. | |
5e05541a | 418 | .TP |
9ba40002 | 419 | .BI \-G " number-of-groups" |
98794d0e | 420 | Specify the number of block groups that will be packed together to |
7a9f055f TT |
421 | create a larger virtual block group (or "flex_bg group") in an |
422 | ext4 filesystem. This improves meta-data locality and performance | |
423 | on meta-data heavy workloads. The number of groups must be a power | |
d04ad325 | 424 | of 2 and may only be specified if the |
7a9f055f TT |
425 | .B flex_bg |
426 | filesystem feature is enabled. | |
9ba40002 | 427 | .TP |
caf8ce4c | 428 | .BI \-i " bytes-per-inode" |
98794d0e | 429 | Specify the bytes/inode ratio. |
3839e657 TT |
430 | .B mke2fs |
431 | creates an inode for every | |
432 | .I bytes-per-inode | |
98794d0e | 433 | bytes of space on the disk. The larger the |
caf8ce4c | 434 | .I bytes-per-inode |
48015ced | 435 | ratio, the fewer inodes will be created. This value generally shouldn't |
98794d0e BS |
436 | be smaller than the blocksize of the filesystem, since in that case more |
437 | inodes would be made than can ever be used. Be warned that it is not | |
e2883e27 PS |
438 | possible to change this ratio on a filesystem after it is created, so be |
439 | careful deciding the correct value for this parameter. Note that resizing | |
ce20096f | 440 | a filesystem changes the number of inodes to maintain this ratio. |
067911ae AD |
441 | .TP |
442 | .BI \-I " inode-size" | |
98794d0e | 443 | Specify the size of each inode in bytes. |
886056bd | 444 | The |
067911ae | 445 | .I inode-size |
98794d0e | 446 | value must be a power of 2 larger or equal to 128. The larger the |
067911ae AD |
447 | .I inode-size |
448 | the more space the inode table will consume, and this reduces the usable | |
98794d0e | 449 | space in the filesystem and can also negatively impact performance. |
886056bd TT |
450 | It is not |
451 | possible to change this value after the filesystem is created. | |
452 | .IP | |
453 | In kernels after 2.6.10 and some | |
454 | earlier vendor kernels it is possible to utilize inodes larger than | |
455 | 128 bytes to store | |
456 | extended attributes for improved performance. | |
e67670c3 | 457 | Extended attributes |
067911ae | 458 | stored in large inodes are not visible with older kernels, and such |
d04ad325 | 459 | filesystems will not be mountable with 2.4 kernels at all. |
886056bd TT |
460 | .IP |
461 | The default inode size is controlled by the | |
462 | .BR mke2fs.conf (5) | |
463 | file. In the | |
464 | .B mke2fs.conf | |
465 | file shipped with e2fsprogs, the default inode size is 256 bytes for | |
466 | most file systems, except for small file systems where the inode size | |
467 | will be 128 bytes. | |
98794d0e | 468 | .TP |
48015ced TT |
469 | .B \-j |
470 | Create the filesystem with an ext3 journal. If the | |
dc2ec525 | 471 | .B \-J |
48015ced | 472 | option is not specified, the default journal parameters will be used to |
98794d0e | 473 | create an appropriately sized journal (given the size of the filesystem) |
48015ced TT |
474 | stored within the filesystem. Note that you must be using a kernel |
475 | which has ext3 support in order to actually make use of the journal. | |
dc2ec525 | 476 | .TP |
48015ced | 477 | .BI \-J " journal-options" |
dc2ec525 | 478 | Create the ext3 journal using options specified on the command-line. |
8ddaa66b TT |
479 | Journal options are comma |
480 | separated, and may take an argument using the equals ('=') sign. | |
48015ced TT |
481 | The following journal options are supported: |
482 | .RS 1.2i | |
dc2ec525 | 483 | .TP |
48015ced | 484 | .BI size= journal-size |
f0865ce4 | 485 | Create an internal journal (i.e., stored inside the filesystem) of size |
98794d0e | 486 | .I journal-size |
8d641749 | 487 | megabytes. |
98794d0e BS |
488 | The size of the journal must be at least 1024 filesystem blocks |
489 | (i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.) | |
57cb2716 SP |
490 | and may be no more than 10,240,000 filesystem blocks or half the total |
491 | file system size (whichever is smaller) | |
b818205f TT |
492 | .TP |
493 | .BI location =journal-location | |
494 | Specify the location of the journal. The argument | |
495 | .I journal-location | |
496 | can either be specified as a block number, or if the number has a units | |
497 | suffix (e.g., 'M', 'G', etc.) interpret it as the offset from the | |
498 | beginning of the file system. | |
48015ced TT |
499 | @JDEV@.TP |
500 | @JDEV@.BI device= external-journal | |
8d641749 TT |
501 | @JDEV@Attach the filesystem to the journal block device located on |
502 | @JDEV@.IR external-journal . | |
503 | @JDEV@The external | |
504 | @JDEV@journal must already have been created using the command | |
505 | @JDEV@.IP | |
2d15576d AD |
506 | @JDEV@.B mke2fs -O journal_dev |
507 | @JDEV@.I external-journal | |
8d641749 TT |
508 | @JDEV@.IP |
509 | @JDEV@Note that | |
510 | @JDEV@.I external-journal | |
511 | @JDEV@must have been created with the | |
512 | @JDEV@same block size as the new filesystem. | |
3024d887 TT |
513 | @JDEV@In addition, while there is support for attaching |
514 | @JDEV@multiple filesystems to a single external journal, | |
98794d0e | 515 | @JDEV@the Linux kernel and |
3024d887 TT |
516 | @JDEV@.BR e2fsck (8) |
517 | @JDEV@do not currently support shared external journals yet. | |
2d15576d AD |
518 | @JDEV@.IP |
519 | @JDEV@Instead of specifying a device name directly, | |
520 | @JDEV@.I external-journal | |
521 | @JDEV@can also be specified by either | |
522 | @JDEV@.BI LABEL= label | |
523 | @JDEV@or | |
524 | @JDEV@.BI UUID= UUID | |
525 | @JDEV@to locate the external journal by either the volume label or UUID | |
526 | @JDEV@stored in the ext2 superblock at the start of the journal. Use | |
527 | @JDEV@.BR dumpe2fs (8) | |
528 | @JDEV@to display a journal device's volume label and UUID. See also the | |
529 | @JDEV@.B -L | |
530 | @JDEV@option of | |
531 | @JDEV@.BR tune2fs (8). | |
8d641749 TT |
532 | .RE |
533 | @JDEV@.IP | |
48015ced TT |
534 | @JDEV@Only one of the |
535 | @JDEV@.BR size " or " device | |
536 | @JDEV@options can be given for a filesystem. | |
48015ced TT |
537 | .TP |
538 | .BI \-l " filename" | |
539 | Read the bad blocks list from | |
98794d0e | 540 | .IR filename . |
3ed57c27 | 541 | Note that the block numbers in the bad block list must be generated |
98794d0e BS |
542 | using the same block size as used by |
543 | .BR mke2fs . | |
544 | As a result, the | |
3ed57c27 | 545 | .B \-c |
98794d0e | 546 | option to |
3ed57c27 TT |
547 | .B mke2fs |
548 | is a much simpler and less error-prone method of checking a disk for bad | |
98794d0e | 549 | blocks before formatting it, as |
3ed57c27 TT |
550 | .B mke2fs |
551 | will automatically pass the correct parameters to the | |
552 | .B badblocks | |
553 | program. | |
48015ced | 554 | .TP |
6a7075df TT |
555 | .BI \-L " new-volume-label" |
556 | Set the volume label for the filesystem to | |
557 | .IR new-volume-label . | |
558 | The maximum length of the | |
559 | volume label is 16 bytes. | |
48015ced TT |
560 | .TP |
561 | .BI \-m " reserved-blocks-percentage" | |
98794d0e | 562 | Specify the percentage of the filesystem blocks reserved for |
029de632 | 563 | the super-user. This avoids fragmentation, and allows root-owned |
98794d0e | 564 | daemons, such as |
029de632 | 565 | .BR syslogd (8), |
98794d0e BS |
566 | to continue to function correctly after non-privileged processes are |
567 | prevented from writing to the filesystem. The default percentage | |
029de632 | 568 | is 5%. |
dc2ec525 | 569 | .TP |
98794d0e BS |
570 | .BI \-M " last-mounted-directory" |
571 | Set the last mounted directory for the filesystem. This might be useful | |
572 | for the sake of utilities that key off of the last mounted directory to | |
bcf5aea2 | 573 | determine where the filesystem should be mounted. |
85ef4ae8 | 574 | .TP |
caf8ce4c | 575 | .B \-n |
98794d0e BS |
576 | Causes |
577 | .B mke2fs | |
578 | to not actually create a filesystem, but display what it | |
1f22ce34 TT |
579 | would do if it were to create a filesystem. This can be used to |
580 | determine the location of the backup superblocks for a particular | |
98794d0e BS |
581 | filesystem, so long as the |
582 | .B mke2fs | |
583 | parameters that were passed when the | |
1f22ce34 | 584 | filesystem was originally created are used again. (With the |
98794d0e | 585 | .B \-n |
1f22ce34 | 586 | option added, of course!) |
2740156b | 587 | .TP |
caf8ce4c | 588 | .BI \-N " number-of-inodes" |
98794d0e BS |
589 | Overrides the default calculation of the number of inodes that should be |
590 | reserved for the filesystem (which is based on the number of blocks and | |
591 | the | |
caf8ce4c | 592 | .I bytes-per-inode |
98794d0e | 593 | ratio). This allows the user to specify the number |
5515e6b4 TT |
594 | of desired inodes directly. |
595 | .TP | |
48015ced | 596 | .BI \-o " creator-os" |
98794d0e BS |
597 | Overrides the default value of the "creator operating system" field of the |
598 | filesystem. The creator field is set by default to the name of the OS the | |
583ccdc3 | 599 | .B mke2fs |
98794d0e | 600 | executable was compiled for. |
1e3472c5 | 601 | .TP |
5c4c3876 | 602 | .B "\-O \fR[^]\fIfeature\fR[,...]" |
98794d0e BS |
603 | Create a filesystem with the given features (filesystem options), |
604 | overriding the default filesystem options. The features that are | |
9dc6ad1e TT |
605 | enabled by default are specified by the |
606 | .I base_features | |
607 | relation, either in the | |
98794d0e | 608 | .I [defaults] |
9dc6ad1e TT |
609 | section in the |
610 | .B /etc/mke2fs.conf | |
3d43836f | 611 | configuration file, |
98794d0e | 612 | or in the |
9dc6ad1e | 613 | .I [fs_types] |
98794d0e | 614 | subsections for the usage types as specified by the |
a26ba650 | 615 | .B \-T |
3d43836f TT |
616 | option, further modified by the |
617 | .I features | |
618 | relation found in the | |
98794d0e BS |
619 | .I [fs_types] |
620 | subsections for the filesystem and usage types. See the | |
3d43836f TT |
621 | .BR mke2fs.conf (5) |
622 | manual page for more details. | |
623 | The filesystem type-specific configuration setting found in the | |
9dc6ad1e TT |
624 | .I [fs_types] |
625 | section will override the global default found in | |
98794d0e | 626 | .IR [defaults] . |
48015ced | 627 | .sp |
98794d0e BS |
628 | The filesystem feature set will be further edited |
629 | using either the feature set specified by this option, | |
630 | or if this option is not given, by the | |
9dc6ad1e | 631 | .I default_features |
98794d0e BS |
632 | relation for the filesystem type being created, or in the |
633 | .I [defaults] | |
9dc6ad1e TT |
634 | section of the configuration file. |
635 | .sp | |
636 | The filesystem feature set is comprised of a list of features, separated | |
637 | by commas, that are to be enabled. To disable a feature, simply | |
5c4c3876 | 638 | prefix the feature name with a caret ('^') character. |
3c22bf7e | 639 | Features with dependencies will not be removed successfully. |
4727c67d | 640 | The pseudo-filesystem feature "none" will clear all filesystem features. |
4727c67d | 641 | .TP |
3c22bf7e TT |
642 | For more information about the features which can be set, please see |
643 | the manual page | |
644 | .BR ext4 (5). | |
1e3472c5 | 645 | .TP |
8d641749 | 646 | .B \-q |
98794d0e | 647 | Quiet execution. Useful if |
8d641749 TT |
648 | .B mke2fs |
649 | is run in a script. | |
650 | .TP | |
48015ced | 651 | .BI \-r " revision" |
a29f4d30 | 652 | Set the filesystem revision for the new filesystem. Note that 1.2 |
98794d0e | 653 | kernels only support revision 0 filesystems. The default is to |
48015ced | 654 | create revision 1 filesystems. |
a29f4d30 | 655 | .TP |
caf8ce4c | 656 | .B \-S |
a6eeac1c AD |
657 | Write superblock and group descriptors only. This is an extreme |
658 | measure to be taken only in the very unlikely case that all of | |
f3db3566 | 659 | the superblock and backup superblocks are corrupted, and a last-ditch |
a6eeac1c | 660 | recovery method is desired by experienced users. It causes |
583ccdc3 | 661 | .B mke2fs |
a6eeac1c AD |
662 | to reinitialize the superblock and group descriptors, while not |
663 | touching the inode table and the block and inode bitmaps. The | |
f3db3566 TT |
664 | .B e2fsck |
665 | program should be run immediately after this option is used, and there | |
a6eeac1c AD |
666 | is no guarantee that any data will be salvageable. Due to the wide |
667 | variety of possible options to | |
668 | .BR mke2fs | |
a7dc56f4 | 669 | that affect the on-disk layout, it is critical to specify exactly |
a6eeac1c AD |
670 | the same format options, such as blocksize, fs-type, feature flags, and |
671 | other tunables when using this option, or the filesystem will be further | |
672 | corrupted. In some cases, such as filesystems that have been resized, | |
673 | or have had features enabled after format time, it is impossible to | |
a7dc56f4 | 674 | overwrite all of the superblocks correctly, and at least some filesystem |
a6eeac1c AD |
675 | corruption will occur. It is best to run this on a full copy of the |
676 | filesystem so other options can be tried if this doesn't work. | |
8d641749 TT |
677 | .\" .TP |
678 | .\" .BI \-t " test" | |
679 | .\" Check the device for bad blocks before creating the file system | |
680 | .\" using the specified test. | |
818180cd | 681 | .TP |
3d43836f | 682 | .BI \-t " fs-type" |
4727c67d UC |
683 | Specify the filesystem type (i.e., ext2, ext3, ext4, etc.) that is |
684 | to be created. | |
98794d0e BS |
685 | If this option is not specified, |
686 | .B mke2fs | |
687 | will pick a default either via how | |
688 | the command was run (for example, using a name of the form mkfs.ext2, | |
3d43836f | 689 | mkfs.ext3, etc.) or via a default as defined by the |
626a2e74 | 690 | .B /etc/mke2fs.conf |
08c8b1ab TT |
691 | file. This option controls which filesystem options are used by |
692 | default, based on the | |
693 | .B fstypes | |
694 | configuration stanza in | |
626a2e74 | 695 | .BR /etc/mke2fs.conf . |
08c8b1ab TT |
696 | .sp |
697 | If the | |
698 | .B \-O | |
699 | option is used to explicitly add or remove filesystem options that | |
700 | should be set in the newly created filesystem, the | |
701 | resulting filesystem may not be supported by the requested | |
702 | .IR fs-type . | |
b7150807 | 703 | (e.g., "\fBmke2fs \-t ext3 \-O extent /dev/sdXX\fR" will create a |
08c8b1ab | 704 | filesystem that is not supported by the ext3 implementation as found in |
93aa0246 | 705 | the Linux kernel; and "\fBmke2fs \-t ext3 \-O ^has_journal /dev/hdXX\fR" |
08c8b1ab TT |
706 | will create a filesystem that does not have a journal and hence will not |
707 | be supported by the ext3 filesystem code in the Linux kernel.) | |
3d43836f TT |
708 | .TP |
709 | .BI \-T " usage-type[,...]" | |
98794d0e BS |
710 | Specify how the filesystem is going to be used, so that |
711 | .B mke2fs | |
3d43836f TT |
712 | can choose optimal filesystem parameters for that use. The usage |
713 | types that are supported are defined in the configuration file | |
626a2e74 | 714 | .BR /etc/mke2fs.conf . |
3d43836f TT |
715 | The user may specify one or more usage types |
716 | using a comma separated list. | |
717 | .sp | |
718 | If this option is is not specified, | |
719 | .B mke2fs | |
720 | will pick a single default usage type based on the size of the filesystem to | |
0745e787 | 721 | be created. If the filesystem size is less than 3 megabytes, |
a4396e9d | 722 | .B mke2fs |
3d43836f TT |
723 | will use the filesystem type |
724 | .IR floppy . | |
0745e787 | 725 | If the filesystem size is greater than or equal to 3 but less than |
3d43836f TT |
726 | 512 megabytes, |
727 | .BR mke2fs (8) | |
9a2767ff | 728 | will use the filesystem type |
3d43836f | 729 | .IR small . |
9a2767ff NK |
730 | If the filesystem size is greater than or equal to 4 terabytes but less than |
731 | 16 terabytes, | |
732 | .BR mke2fs (8) | |
733 | will use the filesystem type | |
734 | .IR big . | |
735 | If the filesystem size is greater than or equal to 16 terabytes, | |
736 | .BR mke2fs (8) | |
737 | will use the filesystem type | |
738 | .IR huge . | |
3d43836f TT |
739 | Otherwise, |
740 | .BR mke2fs (8) | |
741 | will use the default filesystem type | |
742 | .IR default . | |
48015ced | 743 | .TP |
b0afdda1 | 744 | .BI \-U " UUID" |
665ebf37 DD |
745 | Set the universally unique identifier (UUID) of the filesystem to |
746 | .IR UUID . | |
747 | The format of the UUID is a series of hex digits separated by hyphens, | |
748 | like this: | |
749 | "c1b9d5a2-f162-11cf-9ece-0020afc76f16". | |
750 | The | |
751 | .I UUID | |
752 | parameter may also be one of the following: | |
753 | .RS 1.2i | |
754 | .TP | |
755 | .I clear | |
756 | clear the filesystem UUID | |
757 | .TP | |
758 | .I random | |
759 | generate a new randomly-generated UUID | |
760 | .TP | |
761 | .I time | |
762 | generate a new time-based UUID | |
763 | .RE | |
b0afdda1 | 764 | .TP |
48015ced TT |
765 | .B \-v |
766 | Verbose execution. | |
50787ea2 | 767 | .TP |
caf8ce4c | 768 | .B \-V |
98794d0e | 769 | Print the version number of |
818180cd TT |
770 | .B mke2fs |
771 | and exit. | |
2d291b3c DW |
772 | .TP |
773 | .BI \-z " undo_file" | |
774 | Before overwriting a file system block, write the old contents of the block to | |
775 | an undo file. This undo file can be used with e2undo(8) to restore the old | |
776 | contents of the file system should something go wrong. If the empty string is | |
777 | passed as the undo_file argument, the undo file will be written to a file named | |
778 | mke2fs-\fIdevice\fR.e2undo in the directory specified via the | |
779 | \fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive | |
780 | in the configuration file. | |
781 | ||
782 | WARNING: The undo file cannot be used to recover from a power or system crash. | |
5182ad4c NK |
783 | .SH ENVIRONMENT |
784 | .TP | |
785 | .BI MKE2FS_SYNC | |
786 | If set to non-zero integer value, its value is used to determine how often | |
787 | .BR sync (2) | |
788 | is called during inode table initialization. | |
789 | .TP | |
790 | .BI MKE2FS_CONFIG | |
791 | Determines the location of the configuration file (see | |
792 | .BR mke2fs.conf (5)). | |
793 | .TP | |
794 | .BI MKE2FS_FIRST_META_BG | |
795 | If set to non-zero integer value, its value is used to determine first meta | |
796 | block group. This is mostly for debugging purposes. | |
797 | .TP | |
798 | .BI MKE2FS_DEVICE_SECTSIZE | |
75dd3c47 TN |
799 | If set to non-zero integer value, its value is used to determine logical |
800 | sector size of the | |
801 | .IR device . | |
802 | .TP | |
803 | .BI MKE2FS_DEVICE_PHYS_SECTSIZE | |
5182ad4c NK |
804 | If set to non-zero integer value, its value is used to determine physical |
805 | sector size of the | |
806 | .IR device . | |
807 | .TP | |
808 | .BI MKE2FS_SKIP_CHECK_MSG | |
809 | If set, do not show the message of filesystem automatic check caused by | |
810 | mount count or check interval. | |
3839e657 TT |
811 | .SH AUTHOR |
812 | This version of | |
813 | .B mke2fs | |
a418d3ad | 814 | has been written by Theodore Ts'o <tytso@mit.edu>. |
3839e657 TT |
815 | .SH AVAILABILITY |
816 | .B mke2fs | |
98794d0e | 817 | is part of the e2fsprogs package and is available from |
348e43dc | 818 | http://e2fsprogs.sourceforge.net. |
3839e657 | 819 | .SH SEE ALSO |
9dc6ad1e | 820 | .BR mke2fs.conf (5), |
e72a9ba3 | 821 | .BR badblocks (8), |
3839e657 TT |
822 | .BR dumpe2fs (8), |
823 | .BR e2fsck (8), | |
3c22bf7e TT |
824 | .BR tune2fs (8), |
825 | .BR ext4 (5) |