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1 | .\" -*- nroff -*- | |
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. | |
4 | .\" | |
5 | .TH MKE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" | |
6 | .SH NAME | |
7 | mke2fs \- create an ext2/ext3/ext4 filesystem | |
8 | .SH SYNOPSIS | |
9 | .B mke2fs | |
10 | [ | |
11 | .B \-c | |
12 | | | |
13 | .B \-l | |
14 | .I filename | |
15 | ] | |
16 | [ | |
17 | .B \-b | |
18 | .I block-size | |
19 | ] | |
20 | [ | |
21 | .B \-C | |
22 | .I cluster-size | |
23 | ] | |
24 | [ | |
25 | .B \-d | |
26 | .I root-directory | |
27 | ] | |
28 | [ | |
29 | .B \-D | |
30 | ] | |
31 | [ | |
32 | .B \-g | |
33 | .I blocks-per-group | |
34 | ] | |
35 | [ | |
36 | .B \-G | |
37 | .I number-of-groups | |
38 | ] | |
39 | [ | |
40 | .B \-i | |
41 | .I bytes-per-inode | |
42 | ] | |
43 | [ | |
44 | .B \-I | |
45 | .I inode-size | |
46 | ] | |
47 | [ | |
48 | .B \-j | |
49 | ] | |
50 | [ | |
51 | .B \-J | |
52 | .I journal-options | |
53 | ] | |
54 | [ | |
55 | .B \-N | |
56 | .I number-of-inodes | |
57 | ] | |
58 | [ | |
59 | .B \-n | |
60 | ] | |
61 | [ | |
62 | .B \-m | |
63 | .I reserved-blocks-percentage | |
64 | ] | |
65 | [ | |
66 | .B \-o | |
67 | .I creator-os | |
68 | ] | |
69 | [ | |
70 | .B \-O | |
71 | [^]\fIfeature\fR[,...] | |
72 | ] | |
73 | [ | |
74 | .B \-q | |
75 | ] | |
76 | [ | |
77 | .B \-r | |
78 | .I fs-revision-level | |
79 | ] | |
80 | [ | |
81 | .B \-E | |
82 | .I extended-options | |
83 | ] | |
84 | [ | |
85 | .B \-v | |
86 | ] | |
87 | [ | |
88 | .B \-F | |
89 | ] | |
90 | [ | |
91 | .B \-L | |
92 | .I volume-label | |
93 | ] | |
94 | [ | |
95 | .B \-M | |
96 | .I last-mounted-directory | |
97 | ] | |
98 | [ | |
99 | .B \-S | |
100 | ] | |
101 | [ | |
102 | .B \-t | |
103 | .I fs-type | |
104 | ] | |
105 | [ | |
106 | .B \-T | |
107 | .I usage-type | |
108 | ] | |
109 | [ | |
110 | .B \-U | |
111 | .I UUID | |
112 | ] | |
113 | [ | |
114 | .B \-V | |
115 | ] | |
116 | [ | |
117 | .B \-e | |
118 | .I errors-behavior | |
119 | ] | |
120 | [ | |
121 | .B \-z | |
122 | .I undo_file | |
123 | ] | |
124 | .I device | |
125 | [ | |
126 | .I fs-size | |
127 | ] | |
128 | @JDEV@.sp | |
129 | @JDEV@.B "mke2fs \-O journal_dev" | |
130 | @JDEV@[ | |
131 | @JDEV@.B \-b | |
132 | @JDEV@.I block-size | |
133 | @JDEV@] | |
134 | .\" No external-journal specific journal options yet (size is ignored) | |
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@] | |
152 | @JDEV@.I external-journal | |
153 | @JDEV@[ | |
154 | @JDEV@.I fs-size | |
155 | @JDEV@] | |
156 | .SH DESCRIPTION | |
157 | .B mke2fs | |
158 | is used to create an ext2, ext3, or ext4 filesystem, usually in a disk | |
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, | |
180 | .B mke2fs | |
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 | |
196 | .B mkfs.ext3 | |
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. | |
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. | |
207 | .SH OPTIONS | |
208 | .TP | |
209 | .BI \-b " block-size" | |
210 | Specify the size of blocks in bytes. Valid block-size values are 1024, | |
211 | 2048 and 4096 bytes per block. If omitted, | |
212 | block-size is heuristically determined by the filesystem size and | |
213 | the expected usage of the filesystem (see the | |
214 | .B \-T | |
215 | option). If | |
216 | .I block-size | |
217 | is preceded by a negative sign ('-'), then | |
218 | .B mke2fs | |
219 | will use heuristics to determine the | |
220 | appropriate block size, with the constraint that the block size will be | |
221 | at least | |
222 | .I block-size | |
223 | bytes. This is useful for certain hardware devices which require that | |
224 | the blocksize be a multiple of 2k. | |
225 | .TP | |
226 | .B \-c | |
227 | Check the device for bad blocks before creating the file system. If | |
228 | this option is specified twice, then a slower read-write | |
229 | test is used instead of a fast read-only test. | |
230 | .TP | |
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 | |
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. | |
239 | .TP | |
240 | .BI \-d " root-directory" | |
241 | Copy the contents of the given directory into the root directory of the | |
242 | filesystem. | |
243 | .TP | |
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 | |
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 | |
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 | |
272 | .B \-E | |
273 | option used to be | |
274 | .B \-R | |
275 | in earlier versions of | |
276 | .BR mke2fs . | |
277 | The | |
278 | .B \-R | |
279 | option is still accepted for backwards compatibility, but is deprecated. | |
280 | The following extended options are supported: | |
281 | .RS 1.2i | |
282 | .TP | |
283 | .BI encoding= encoding-name | |
284 | Enable the | |
285 | .I casefold | |
286 | feature in the super block and set | |
287 | .I encoding-name | |
288 | as the encoding to be used. If | |
289 | .I encoding-name | |
290 | is not specified, the encoding defined in | |
291 | .BR mke2fs.conf (5) | |
292 | is used. | |
293 | .TP | |
294 | .BI encoding_flags= encoding-flags | |
295 | Define parameters for file name character encoding operations. If a | |
296 | flag is not changed using this parameter, its default value is used. | |
297 | .I encoding-flags | |
298 | should be a comma-separated lists of flags to be enabled. To disable a | |
299 | flag, add it to the list with the prefix "no". | |
300 | ||
301 | The only flag that can be set right now is | |
302 | .I strict | |
303 | which means that invalid strings should be rejected by the file system. | |
304 | In the default configuration, the | |
305 | .I strict | |
306 | flag is disabled. | |
307 | .TP | |
308 | .BI mmp_update_interval= interval | |
309 | Adjust the initial MMP update interval to | |
310 | .I interval | |
311 | seconds. Specifying an | |
312 | .I interval | |
313 | of 0 means to use the default interval. The specified interval must | |
314 | be less than 300 seconds. Requires that the | |
315 | .B mmp | |
316 | feature be enabled. | |
317 | .TP | |
318 | .BI stride= stride-size | |
319 | Configure the filesystem for a RAID array with | |
320 | .I stride-size | |
321 | filesystem blocks. This is the number of blocks read or written to disk | |
322 | before moving to the next disk, which is sometimes referred to as the | |
323 | .I chunk size. | |
324 | This mostly affects placement of filesystem metadata like bitmaps at | |
325 | .B mke2fs | |
326 | time to avoid placing them on a single disk, which can hurt performance. | |
327 | It may also be used by the block allocator. | |
328 | .TP | |
329 | .BI stripe_width= stripe-width | |
330 | Configure the filesystem for a RAID array with | |
331 | .I stripe-width | |
332 | filesystem blocks per stripe. This is typically stride-size * N, where | |
333 | N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one | |
334 | parity disk, so N will be the number of disks in the array minus 1). | |
335 | This allows the block allocator to prevent read-modify-write of the | |
336 | parity in a RAID stripe if possible when the data is written. | |
337 | .TP | |
338 | .BI offset= offset | |
339 | Create the filesystem at an offset from the beginning of the device or | |
340 | file. This can be useful when creating disk images for virtual machines. | |
341 | .TP | |
342 | .BI resize= max-online-resize | |
343 | Reserve enough space so that the block group descriptor table can grow | |
344 | to support a filesystem that has | |
345 | .I max-online-resize | |
346 | blocks. | |
347 | .TP | |
348 | .B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] | |
349 | If enabled and the uninit_bg feature is enabled, the inode table will | |
350 | not be fully initialized by | |
351 | .BR mke2fs . | |
352 | This speeds up filesystem | |
353 | initialization noticeably, but it requires the kernel to finish | |
354 | initializing the filesystem in the background when the filesystem is | |
355 | first mounted. If the option value is omitted, it defaults to 1 to | |
356 | enable lazy inode table zeroing. | |
357 | .TP | |
358 | .B lazy_journal_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR] | |
359 | If enabled, the journal inode will not be fully zeroed out by | |
360 | .BR mke2fs . | |
361 | This speeds up filesystem initialization noticeably, but carries some | |
362 | small risk if the system crashes before the journal has been overwritten | |
363 | entirely one time. If the option value is omitted, it defaults to 1 to | |
364 | enable lazy journal inode zeroing. | |
365 | .TP | |
366 | .B no_copy_xattrs | |
367 | Normally | |
368 | .B mke2fs | |
369 | will copy the extended attributes of the files in the directory | |
370 | hierarchy specified via the (optional) | |
371 | .B \-d | |
372 | option. This will disable the copy and leaves the files in the newly | |
373 | created file system without any extended attributes. | |
374 | .TP | |
375 | .BI num_backup_sb= <0|1|2> | |
376 | If the | |
377 | .B sparse_super2 | |
378 | file system feature is enabled this option controls whether there will | |
379 | be 0, 1, or 2 backup superblocks created in the file system. | |
380 | .TP | |
381 | .B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR] | |
382 | Place the allocation bitmaps and the inode table at the beginning of the | |
383 | disk. This option requires that the flex_bg file system feature to be | |
384 | enabled in order for it to have effect, and will also create the journal | |
385 | at the beginning of the file system. This option is useful for flash | |
386 | devices that use SLC flash at the beginning of the disk. | |
387 | It also maximizes the range of contiguous data blocks, which | |
388 | can be useful for certain specialized use cases, such as supported | |
389 | Shingled Drives. | |
390 | .TP | |
391 | .BI root_owner [=uid:gid] | |
392 | Specify the numeric user and group ID of the root directory. If no UID:GID | |
393 | is specified, use the user and group ID of the user running \fBmke2fs\fR. | |
394 | In \fBmke2fs\fR 1.42 and earlier the UID and GID of the root directory were | |
395 | set by default to the UID and GID of the user running the mke2fs command. | |
396 | The \fBroot_owner=\fR option allows explicitly specifying these values, | |
397 | and avoid side-effects for users that do not expect the contents of the | |
398 | filesystem to change based on the user running \fBmke2fs\fR. | |
399 | .TP | |
400 | .B test_fs | |
401 | Set a flag in the filesystem superblock indicating that it may be | |
402 | mounted using experimental kernel code, such as the ext4dev filesystem. | |
403 | .TP | |
404 | .B discard | |
405 | Attempt to discard blocks at mkfs time (discarding blocks initially is useful | |
406 | on solid state devices and sparse / thin-provisioned storage). When the device | |
407 | advertises that discard also zeroes data (any subsequent read after the discard | |
408 | and before write returns zero), then mark all not-yet-zeroed inode tables as | |
409 | zeroed. This significantly speeds up filesystem initialization. This is set | |
410 | as default. | |
411 | .TP | |
412 | .B nodiscard | |
413 | Do not attempt to discard blocks at mkfs time. | |
414 | .TP | |
415 | .B quotatype | |
416 | Specify the which quota types (usrquota, grpquota, prjquota) which | |
417 | should be enabled in the created file system. The argument of this | |
418 | extended option should be a colon separated list. This option has | |
419 | effect only if the | |
420 | .B quota | |
421 | feature is set. The default quota types to be initialized if this | |
422 | option is not specified is both user and group quotas. If the project | |
423 | feature is enabled that project quotas will be initialized as well. | |
424 | .RE | |
425 | .TP | |
426 | .B \-F | |
427 | Force | |
428 | .B mke2fs | |
429 | to create a filesystem, even if the specified device is not a partition | |
430 | on a block special device, or if other parameters do not make sense. | |
431 | In order to force | |
432 | .B mke2fs | |
433 | to create a filesystem even if the filesystem appears to be in use | |
434 | or is mounted (a truly dangerous thing to do), this option must be | |
435 | specified twice. | |
436 | .TP | |
437 | .BI \-g " blocks-per-group" | |
438 | Specify the number of blocks in a block group. There is generally no | |
439 | reason for the user to ever set this parameter, as the default is optimal | |
440 | for the filesystem. (For administrators who are creating | |
441 | filesystems on RAID arrays, it is preferable to use the | |
442 | .I stride | |
443 | RAID parameter as part of the | |
444 | .B \-E | |
445 | option rather than manipulating the number of blocks per group.) | |
446 | This option is generally used by developers who | |
447 | are developing test cases. | |
448 | .IP | |
449 | If the bigalloc feature is enabled, the | |
450 | .B \-g | |
451 | option will specify the number of clusters in a block group. | |
452 | .TP | |
453 | .BI \-G " number-of-groups" | |
454 | Specify the number of block groups that will be packed together to | |
455 | create a larger virtual block group (or "flex_bg group") in an | |
456 | ext4 filesystem. This improves meta-data locality and performance | |
457 | on meta-data heavy workloads. The number of groups must be a power | |
458 | of 2 and may only be specified if the | |
459 | .B flex_bg | |
460 | filesystem feature is enabled. | |
461 | .TP | |
462 | .BI \-i " bytes-per-inode" | |
463 | Specify the bytes/inode ratio. | |
464 | .B mke2fs | |
465 | creates an inode for every | |
466 | .I bytes-per-inode | |
467 | bytes of space on the disk. The larger the | |
468 | .I bytes-per-inode | |
469 | ratio, the fewer inodes will be created. This value generally shouldn't | |
470 | be smaller than the blocksize of the filesystem, since in that case more | |
471 | inodes would be made than can ever be used. Be warned that it is not | |
472 | possible to change this ratio on a filesystem after it is created, so be | |
473 | careful deciding the correct value for this parameter. Note that resizing | |
474 | a filesystem changes the number of inodes to maintain this ratio. | |
475 | .TP | |
476 | .BI \-I " inode-size" | |
477 | Specify the size of each inode in bytes. | |
478 | The | |
479 | .I inode-size | |
480 | value must be a power of 2 larger or equal to 128. The larger the | |
481 | .I inode-size | |
482 | the more space the inode table will consume, and this reduces the usable | |
483 | space in the filesystem and can also negatively impact performance. | |
484 | It is not | |
485 | possible to change this value after the filesystem is created. | |
486 | .IP | |
487 | In kernels after 2.6.10 and some | |
488 | earlier vendor kernels it is possible to utilize inodes larger than | |
489 | 128 bytes to store | |
490 | extended attributes for improved performance. | |
491 | Extended attributes | |
492 | stored in large inodes are not visible with older kernels, and such | |
493 | filesystems will not be mountable with 2.4 kernels at all. | |
494 | .IP | |
495 | The default inode size is controlled by the | |
496 | .BR mke2fs.conf (5) | |
497 | file. In the | |
498 | .B mke2fs.conf | |
499 | file shipped with e2fsprogs, the default inode size is 256 bytes for | |
500 | most file systems, except for small file systems where the inode size | |
501 | will be 128 bytes. | |
502 | .TP | |
503 | .B \-j | |
504 | Create the filesystem with an ext3 journal. If the | |
505 | .B \-J | |
506 | option is not specified, the default journal parameters will be used to | |
507 | create an appropriately sized journal (given the size of the filesystem) | |
508 | stored within the filesystem. Note that you must be using a kernel | |
509 | which has ext3 support in order to actually make use of the journal. | |
510 | .TP | |
511 | .BI \-J " journal-options" | |
512 | Create the ext3 journal using options specified on the command-line. | |
513 | Journal options are comma | |
514 | separated, and may take an argument using the equals ('=') sign. | |
515 | The following journal options are supported: | |
516 | .RS 1.2i | |
517 | .TP | |
518 | .BI size= journal-size | |
519 | Create an internal journal (i.e., stored inside the filesystem) of size | |
520 | .I journal-size | |
521 | megabytes. | |
522 | The size of the journal must be at least 1024 filesystem blocks | |
523 | (i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.) | |
524 | and may be no more than 10,240,000 filesystem blocks or half the total | |
525 | file system size (whichever is smaller) | |
526 | .TP | |
527 | .BI location =journal-location | |
528 | Specify the location of the journal. The argument | |
529 | .I journal-location | |
530 | can either be specified as a block number, or if the number has a units | |
531 | suffix (e.g., 'M', 'G', etc.) interpret it as the offset from the | |
532 | beginning of the file system. | |
533 | @JDEV@.TP | |
534 | @JDEV@.BI device= external-journal | |
535 | @JDEV@Attach the filesystem to the journal block device located on | |
536 | @JDEV@.IR external-journal . | |
537 | @JDEV@The external | |
538 | @JDEV@journal must already have been created using the command | |
539 | @JDEV@.IP | |
540 | @JDEV@.B mke2fs -O journal_dev | |
541 | @JDEV@.I external-journal | |
542 | @JDEV@.IP | |
543 | @JDEV@Note that | |
544 | @JDEV@.I external-journal | |
545 | @JDEV@must have been created with the | |
546 | @JDEV@same block size as the new filesystem. | |
547 | @JDEV@In addition, while there is support for attaching | |
548 | @JDEV@multiple filesystems to a single external journal, | |
549 | @JDEV@the Linux kernel and | |
550 | @JDEV@.BR e2fsck (8) | |
551 | @JDEV@do not currently support shared external journals yet. | |
552 | @JDEV@.IP | |
553 | @JDEV@Instead of specifying a device name directly, | |
554 | @JDEV@.I external-journal | |
555 | @JDEV@can also be specified by either | |
556 | @JDEV@.BI LABEL= label | |
557 | @JDEV@or | |
558 | @JDEV@.BI UUID= UUID | |
559 | @JDEV@to locate the external journal by either the volume label or UUID | |
560 | @JDEV@stored in the ext2 superblock at the start of the journal. Use | |
561 | @JDEV@.BR dumpe2fs (8) | |
562 | @JDEV@to display a journal device's volume label and UUID. See also the | |
563 | @JDEV@.B -L | |
564 | @JDEV@option of | |
565 | @JDEV@.BR tune2fs (8). | |
566 | .RE | |
567 | @JDEV@.IP | |
568 | @JDEV@Only one of the | |
569 | @JDEV@.BR size " or " device | |
570 | @JDEV@options can be given for a filesystem. | |
571 | .TP | |
572 | .BI \-l " filename" | |
573 | Read the bad blocks list from | |
574 | .IR filename . | |
575 | Note that the block numbers in the bad block list must be generated | |
576 | using the same block size as used by | |
577 | .BR mke2fs . | |
578 | As a result, the | |
579 | .B \-c | |
580 | option to | |
581 | .B mke2fs | |
582 | is a much simpler and less error-prone method of checking a disk for bad | |
583 | blocks before formatting it, as | |
584 | .B mke2fs | |
585 | will automatically pass the correct parameters to the | |
586 | .B badblocks | |
587 | program. | |
588 | .TP | |
589 | .BI \-L " new-volume-label" | |
590 | Set the volume label for the filesystem to | |
591 | .IR new-volume-label . | |
592 | The maximum length of the | |
593 | volume label is 16 bytes. | |
594 | .TP | |
595 | .BI \-m " reserved-blocks-percentage" | |
596 | Specify the percentage of the filesystem blocks reserved for | |
597 | the super-user. This avoids fragmentation, and allows root-owned | |
598 | daemons, such as | |
599 | .BR syslogd (8), | |
600 | to continue to function correctly after non-privileged processes are | |
601 | prevented from writing to the filesystem. The default percentage | |
602 | is 5%. | |
603 | .TP | |
604 | .BI \-M " last-mounted-directory" | |
605 | Set the last mounted directory for the filesystem. This might be useful | |
606 | for the sake of utilities that key off of the last mounted directory to | |
607 | determine where the filesystem should be mounted. | |
608 | .TP | |
609 | .B \-n | |
610 | Causes | |
611 | .B mke2fs | |
612 | to not actually create a filesystem, but display what it | |
613 | would do if it were to create a filesystem. This can be used to | |
614 | determine the location of the backup superblocks for a particular | |
615 | filesystem, so long as the | |
616 | .B mke2fs | |
617 | parameters that were passed when the | |
618 | filesystem was originally created are used again. (With the | |
619 | .B \-n | |
620 | option added, of course!) | |
621 | .TP | |
622 | .BI \-N " number-of-inodes" | |
623 | Overrides the default calculation of the number of inodes that should be | |
624 | reserved for the filesystem (which is based on the number of blocks and | |
625 | the | |
626 | .I bytes-per-inode | |
627 | ratio). This allows the user to specify the number | |
628 | of desired inodes directly. | |
629 | .TP | |
630 | .BI \-o " creator-os" | |
631 | Overrides the default value of the "creator operating system" field of the | |
632 | filesystem. The creator field is set by default to the name of the OS the | |
633 | .B mke2fs | |
634 | executable was compiled for. | |
635 | .TP | |
636 | .B "\-O \fR[^]\fIfeature\fR[,...]" | |
637 | Create a filesystem with the given features (filesystem options), | |
638 | overriding the default filesystem options. The features that are | |
639 | enabled by default are specified by the | |
640 | .I base_features | |
641 | relation, either in the | |
642 | .I [defaults] | |
643 | section in the | |
644 | .B /etc/mke2fs.conf | |
645 | configuration file, | |
646 | or in the | |
647 | .I [fs_types] | |
648 | subsections for the usage types as specified by the | |
649 | .B \-T | |
650 | option, further modified by the | |
651 | .I features | |
652 | relation found in the | |
653 | .I [fs_types] | |
654 | subsections for the filesystem and usage types. See the | |
655 | .BR mke2fs.conf (5) | |
656 | manual page for more details. | |
657 | The filesystem type-specific configuration setting found in the | |
658 | .I [fs_types] | |
659 | section will override the global default found in | |
660 | .IR [defaults] . | |
661 | .sp | |
662 | The filesystem feature set will be further edited | |
663 | using either the feature set specified by this option, | |
664 | or if this option is not given, by the | |
665 | .I default_features | |
666 | relation for the filesystem type being created, or in the | |
667 | .I [defaults] | |
668 | section of the configuration file. | |
669 | .sp | |
670 | The filesystem feature set is comprised of a list of features, separated | |
671 | by commas, that are to be enabled. To disable a feature, simply | |
672 | prefix the feature name with a caret ('^') character. | |
673 | Features with dependencies will not be removed successfully. | |
674 | The pseudo-filesystem feature "none" will clear all filesystem features. | |
675 | .TP | |
676 | For more information about the features which can be set, please see | |
677 | the manual page | |
678 | .BR ext4 (5). | |
679 | .TP | |
680 | .B \-q | |
681 | Quiet execution. Useful if | |
682 | .B mke2fs | |
683 | is run in a script. | |
684 | .TP | |
685 | .BI \-r " revision" | |
686 | Set the filesystem revision for the new filesystem. Note that 1.2 | |
687 | kernels only support revision 0 filesystems. The default is to | |
688 | create revision 1 filesystems. | |
689 | .TP | |
690 | .B \-S | |
691 | Write superblock and group descriptors only. This is an extreme | |
692 | measure to be taken only in the very unlikely case that all of | |
693 | the superblock and backup superblocks are corrupted, and a last-ditch | |
694 | recovery method is desired by experienced users. It causes | |
695 | .B mke2fs | |
696 | to reinitialize the superblock and group descriptors, while not | |
697 | touching the inode table and the block and inode bitmaps. The | |
698 | .B e2fsck | |
699 | program should be run immediately after this option is used, and there | |
700 | is no guarantee that any data will be salvageable. Due to the wide | |
701 | variety of possible options to | |
702 | .B mke2fs | |
703 | that affect the on-disk layout, it is critical to specify exactly | |
704 | the same format options, such as blocksize, fs-type, feature flags, and | |
705 | other tunables when using this option, or the filesystem will be further | |
706 | corrupted. In some cases, such as filesystems that have been resized, | |
707 | or have had features enabled after format time, it is impossible to | |
708 | overwrite all of the superblocks correctly, and at least some filesystem | |
709 | corruption will occur. It is best to run this on a full copy of the | |
710 | filesystem so other options can be tried if this doesn't work. | |
711 | .\" .TP | |
712 | .\" .BI \-t " test" | |
713 | .\" Check the device for bad blocks before creating the file system | |
714 | .\" using the specified test. | |
715 | .TP | |
716 | .BI \-t " fs-type" | |
717 | Specify the filesystem type (i.e., ext2, ext3, ext4, etc.) that is | |
718 | to be created. | |
719 | If this option is not specified, | |
720 | .B mke2fs | |
721 | will pick a default either via how | |
722 | the command was run (for example, using a name of the form mkfs.ext2, | |
723 | mkfs.ext3, etc.) or via a default as defined by the | |
724 | .B /etc/mke2fs.conf | |
725 | file. This option controls which filesystem options are used by | |
726 | default, based on the | |
727 | .B fstypes | |
728 | configuration stanza in | |
729 | .BR /etc/mke2fs.conf . | |
730 | .sp | |
731 | If the | |
732 | .B \-O | |
733 | option is used to explicitly add or remove filesystem options that | |
734 | should be set in the newly created filesystem, the | |
735 | resulting filesystem may not be supported by the requested | |
736 | .IR fs-type . | |
737 | (e.g., "\fBmke2fs \-t ext3 \-O extent /dev/sdXX\fR" will create a | |
738 | filesystem that is not supported by the ext3 implementation as found in | |
739 | the Linux kernel; and "\fBmke2fs \-t ext3 \-O ^has_journal /dev/hdXX\fR" | |
740 | will create a filesystem that does not have a journal and hence will not | |
741 | be supported by the ext3 filesystem code in the Linux kernel.) | |
742 | .TP | |
743 | .BI \-T " usage-type[,...]" | |
744 | Specify how the filesystem is going to be used, so that | |
745 | .B mke2fs | |
746 | can choose optimal filesystem parameters for that use. The usage | |
747 | types that are supported are defined in the configuration file | |
748 | .BR /etc/mke2fs.conf . | |
749 | The user may specify one or more usage types | |
750 | using a comma separated list. | |
751 | .sp | |
752 | If this option is is not specified, | |
753 | .B mke2fs | |
754 | will pick a single default usage type based on the size of the filesystem to | |
755 | be created. If the filesystem size is less than 3 megabytes, | |
756 | .B mke2fs | |
757 | will use the filesystem type | |
758 | .IR floppy . | |
759 | If the filesystem size is greater than or equal to 3 but less than | |
760 | 512 megabytes, | |
761 | .BR mke2fs (8) | |
762 | will use the filesystem type | |
763 | .IR small . | |
764 | If the filesystem size is greater than or equal to 4 terabytes but less than | |
765 | 16 terabytes, | |
766 | .BR mke2fs (8) | |
767 | will use the filesystem type | |
768 | .IR big . | |
769 | If the filesystem size is greater than or equal to 16 terabytes, | |
770 | .BR mke2fs (8) | |
771 | will use the filesystem type | |
772 | .IR huge . | |
773 | Otherwise, | |
774 | .BR mke2fs (8) | |
775 | will use the default filesystem type | |
776 | .IR default . | |
777 | .TP | |
778 | .BI \-U " UUID" | |
779 | Set the universally unique identifier (UUID) of the filesystem to | |
780 | .IR UUID . | |
781 | The format of the UUID is a series of hex digits separated by hyphens, | |
782 | like this: | |
783 | "c1b9d5a2-f162-11cf-9ece-0020afc76f16". | |
784 | The | |
785 | .I UUID | |
786 | parameter may also be one of the following: | |
787 | .RS 1.2i | |
788 | .TP | |
789 | .I clear | |
790 | clear the filesystem UUID | |
791 | .TP | |
792 | .I random | |
793 | generate a new randomly-generated UUID | |
794 | .TP | |
795 | .I time | |
796 | generate a new time-based UUID | |
797 | .RE | |
798 | .TP | |
799 | .B \-v | |
800 | Verbose execution. | |
801 | .TP | |
802 | .B \-V | |
803 | Print the version number of | |
804 | .B mke2fs | |
805 | and exit. | |
806 | .TP | |
807 | .BI \-z " undo_file" | |
808 | Before overwriting a file system block, write the old contents of the block to | |
809 | an undo file. This undo file can be used with e2undo(8) to restore the old | |
810 | contents of the file system should something go wrong. If the empty string is | |
811 | passed as the undo_file argument, the undo file will be written to a file named | |
812 | mke2fs-\fIdevice\fR.e2undo in the directory specified via the | |
813 | \fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive | |
814 | in the configuration file. | |
815 | ||
816 | WARNING: The undo file cannot be used to recover from a power or system crash. | |
817 | .SH ENVIRONMENT | |
818 | .TP | |
819 | .B MKE2FS_SYNC | |
820 | If set to non-zero integer value, its value is used to determine how often | |
821 | .BR sync (2) | |
822 | is called during inode table initialization. | |
823 | .TP | |
824 | .B MKE2FS_CONFIG | |
825 | Determines the location of the configuration file (see | |
826 | .BR mke2fs.conf (5)). | |
827 | .TP | |
828 | .B MKE2FS_FIRST_META_BG | |
829 | If set to non-zero integer value, its value is used to determine first meta | |
830 | block group. This is mostly for debugging purposes. | |
831 | .TP | |
832 | .B MKE2FS_DEVICE_SECTSIZE | |
833 | If set to non-zero integer value, its value is used to determine logical | |
834 | sector size of the | |
835 | .IR device . | |
836 | .TP | |
837 | .B MKE2FS_DEVICE_PHYS_SECTSIZE | |
838 | If set to non-zero integer value, its value is used to determine physical | |
839 | sector size of the | |
840 | .IR device . | |
841 | .TP | |
842 | .B MKE2FS_SKIP_CHECK_MSG | |
843 | If set, do not show the message of filesystem automatic check caused by | |
844 | mount count or check interval. | |
845 | .SH AUTHOR | |
846 | This version of | |
847 | .B mke2fs | |
848 | has been written by Theodore Ts'o <tytso@mit.edu>. | |
849 | .SH AVAILABILITY | |
850 | .B mke2fs | |
851 | is part of the e2fsprogs package and is available from | |
852 | http://e2fsprogs.sourceforge.net. | |
853 | .SH SEE ALSO | |
854 | .BR mke2fs.conf (5), | |
855 | .BR badblocks (8), | |
856 | .BR dumpe2fs (8), | |
857 | .BR e2fsck (8), | |
858 | .BR tune2fs (8), | |
859 | .BR ext4 (5) |