1mkfs.xfs(8) System Manager's Manual mkfs.xfs(8)
2
6 mkfs.xfs - construct an XFS filesystem
7
9 mkfs.xfs [ -b block_size_options ] [ -m global_metadata_options ] [ -d
10 data_section_options ] [ -f ] [ -i inode_options ] [ -l log_sec‐
11 tion_options ] [ -n naming_options ] [ -p protofile ] [ -q ] [ -r real‐
12 time_section_options ] [ -s sector_size_options ] [ -L label ] [ -N ] [
13 -K ] device
14 mkfs.xfs -V
15
17 mkfs.xfs constructs an XFS filesystem by writing on a special file
18 using the values found in the arguments of the command line. It is
19 invoked automatically by mkfs(8) when it is given the -t xfs option.
20 In its simplest (and most commonly used form), the size of the filesys‐
22 tem is determined from the disk driver. As an example, to make a
23 filesystem with an internal log on the first partition on the first
24 SCSI disk, use:
25 mkfs.xfs /dev/sda1
27 The metadata log can be placed on another device to reduce the number
29 of disk seeks. To create a filesystem on the first partition on the
30 first SCSI disk with a 10MiB log located on the first partition on the
31 second SCSI disk, use:
32 mkfs.xfs -l logdev=/dev/sdb1,size=10m /dev/sda1
34 Each of the option elements in the argument list above can be given as
36 multiple comma-separated suboptions if multiple suboptions apply to the
37 same option. Equivalently, each main option can be given multiple
38 times with different suboptions. For example, -l internal,size=10m and
39 -l internal -l size=10m are equivalent.
40 In the descriptions below, sizes are given in sectors, bytes, blocks,
42 kilobytes, megabytes, gigabytes, etc. Sizes are treated as hexadecimal
43 if prefixed by 0x or 0X, octal if prefixed by 0, or decimal otherwise.
44 The following lists possible multiplication suffixes:
45 s - multiply by sector size (default = 512, see -s option
46 below).
47 b - multiply by filesystem block size (default = 4K, see -b
48 option below).
49 k - multiply by one kilobyte (1,024 bytes).
50 m - multiply by one megabyte (1,048,576 bytes).
51 g - multiply by one gigabyte (1,073,741,824 bytes).
52 t - multiply by one terabyte (1,099,511,627,776 bytes).
53 p - multiply by one petabyte (1,024 terabytes).
54 e - multiply by one exabyte (1,048,576 terabytes).
55 When specifying parameters in units of sectors or filesystem blocks,
57 the -s option or the -b option first needs to be added to the command
58 line. Failure to specify the size of the units will result in illegal
59 value errors when parameters are quantified in those units.
60 Many feature options allow an optional argument of 0 or 1, to explic‐
62 itly disable or enable the functionality.
63
65 -b block_size_options
66 This option specifies the fundamental block size of the filesys‐
67 tem. The valid block_size_option is:
68 size=value
70 The filesystem block size is specified with a value
71 in bytes. The default value is 4096 bytes (4 KiB),
72 the minimum is 512, and the maximum is 65536 (64
73 KiB).
74 To specify any options on the command line in units
76 of filesystem blocks, this option must be specified
77 first so that the filesystem block size is applied
78 consistently to all options.
79 Although mkfs.xfs will accept any of these values
81 and create a valid filesystem, XFS on Linux can only
82 mount filesystems with pagesize or smaller blocks.
83 -m global_metadata_options
85 These options specify metadata format options that either apply
86 to the entire filesystem or aren't easily characterised by a
87 specific functionality group. The valid global_metadata_options
88 are:
89 crc=value
91 This is used to create a filesystem which maintains
92 and checks CRC information in all metadata objects
93 on disk. The value is either 0 to disable the fea‐
94 ture, or 1 to enable the use of CRCs.
95 CRCs enable enhanced error detection due to hardware
97 issues, whilst the format changes also improves
98 crash recovery algorithms and the ability of various
99 tools to validate and repair metadata corruptions
100 when they are found. The CRC algorithm used is
101 CRC32c, so the overhead is dependent on CPU archi‐
102 tecture as some CPUs have hardware acceleration of
103 this algorithm. Typically the overhead of calculat‐
104 ing and checking the CRCs is not noticeable in nor‐
105 mal operation.
106 By default, mkfs.xfs will enable metadata CRCs.
108 finobt=value
110 This option enables the use of a separate free inode
111 btree index in each allocation group. The value is
112 either 0 to disable the feature, or 1 to create a
113 free inode btree in each allocation group.
114 The free inode btree mirrors the existing allocated
116 inode btree index which indexes both used and free
117 inodes. The free inode btree does not index used
118 inodes, allowing faster, more consistent inode allo‐
119 cation performance as filesystems age.
120 By default, mkfs.xfs will create free inode btrees
122 for filesystems created with the (default) -m crc=1
123 option set. When the option -m crc=0 is used, the
124 free inode btree feature is not supported and is
125 disabled.
126 uuid=value
128 Use the given value as the filesystem UUID for the
129 newly created filesystem. The default is to gener‐
130 ate a random UUID.
131 rmapbt=value
133 This option enables the creation of a reverse-map‐
134 ping btree index in each allocation group. The
135 value is either 0 to disable the feature, or 1 to
136 create the btree.
137 The reverse mapping btree maps filesystem blocks to
139 the owner of the filesystem block. Most of the map‐
140 pings will be to an inode number and an offset,
141 though there will also be mappings to filesystem
142 metadata. This secondary metadata can be used to
143 validate the primary metadata or to pinpoint exactly
144 which data has been lost when a disk error occurs.
145 By default, mkfs.xfs will not create reverse mapping
147 btrees. This feature is only available for filesys‐
148 tems created with the (default) -m crc=1 option set.
149 When the option -m crc=0 is used, the reverse map‐
150 ping btree feature is not supported and is disabled.
151 reflink=value
153 This option enables the use of a separate reference
154 count btree index in each allocation group. The
155 value is either 0 to disable the feature, or 1 to
156 create a reference count btree in each allocation
157 group.
158 The reference count btree enables the sharing of
160 physical extents between the data forks of different
161 files, which is commonly known as "reflink". Unlike
162 traditional Unix filesystems which assume that every
163 inode and logical block pair map to a unique physi‐
164 cal block, a reflink-capable XFS filesystem removes
165 the uniqueness requirement, allowing up to four bil‐
166 lion arbitrary inode/logical block pairs to map to a
167 physical block. If a program tries to write to a
168 multiply-referenced block in a file, the write will
169 be redirected to a new block, and that file's logi‐
170 cal-to-physical mapping will be changed to the new
171 block ("copy on write"). This feature enables the
172 creation of per-file snapshots and deduplication.
173 It is only available for the data forks of regular
174 files.
175 By default, mkfs.xfs will not create reference count
177 btrees and therefore will not enable the reflink
178 feature. This feature is only available for
179 filesystems created with the (default) -m crc=1
180 option set. When the option -m crc=0 is used, the
181 reference count btree feature is not supported and
182 reflink is disabled.
183 -d data_section_options
185 These options specify the location, size, and other parameters
186 of the data section of the filesystem. The valid data_sec‐
187 tion_options are:
188 agcount=value
190 This is used to specify the number of allocation
191 groups. The data section of the filesystem is
192 divided into allocation groups to improve the per‐
193 formance of XFS. More allocation groups imply that
194 more parallelism can be achieved when allocating
195 blocks and inodes. The minimum allocation group size
196 is 16 MiB; the maximum size is just under 1 TiB.
197 The data section of the filesystem is divided into
198 value allocation groups (default value is scaled
199 automatically based on the underlying device size).
200 agsize=value
202 This is an alternative to using the agcount subop‐
203 tion. The value is the desired size of the alloca‐
204 tion group expressed in bytes (usually using the m
205 or g suffixes). This value must be a multiple of
206 the filesystem block size, and must be at least
207 16MiB, and no more than 1TiB, and may be automati‐
208 cally adjusted to properly align with the stripe
209 geometry. The agcount and agsize suboptions are
210 mutually exclusive.
211 cowextsize=value
213 Set the copy-on-write extent size hint on all inodes
214 created by mkfs.xfs. The value must be provided in
215 units of filesystem blocks. If the value is zero,
216 the default value (currently 32 blocks) will be
217 used. Directories will pass on this hint to newly
218 created children.
219 name=value
221 This can be used to specify the name of the special
222 file containing the filesystem. In this case, the
223 log section must be specified as internal (with a
224 size, see the -l option below) and there can be no
225 real-time section.
226 file[=value]
228 This is used to specify that the file given by the
229 name suboption is a regular file. The value is
230 either 0 or 1, with 1 signifying that the file is
231 regular. This suboption is used only to make a
232 filesystem image. If the value is omitted then 1 is
233 assumed.
234 size=value
236 This is used to specify the size of the data sec‐
237 tion. This suboption is required if -d file[=1] is
238 given. Otherwise, it is only needed if the filesys‐
239 tem should occupy less space than the size of the
240 special file.
241 sunit=value
243 This is used to specify the stripe unit for a RAID
244 device or a logical volume. The value has to be
245 specified in 512-byte block units. Use the su subop‐
246 tion to specify the stripe unit size in bytes. This
247 suboption ensures that data allocations will be
248 stripe unit aligned when the current end of file is
249 being extended and the file size is larger than
250 512KiB. Also inode allocations and the internal log
251 will be stripe unit aligned.
252 su=value
254 This is an alternative to using sunit. The su sub‐
255 option is used to specify the stripe unit for a RAID
256 device or a striped logical volume. The value has to
257 be specified in bytes, (usually using the m or g
258 suffixes). This value must be a multiple of the
259 filesystem block size.
260 swidth=value
262 This is used to specify the stripe width for a RAID
263 device or a striped logical volume. The value has to
264 be specified in 512-byte block units. Use the sw
265 suboption to specify the stripe width size in bytes.
266 This suboption is required if -d sunit has been
267 specified and it has to be a multiple of the -d
268 sunit suboption.
269 sw=value
271 suboption is an alternative to using swidth. The sw
272 suboption is used to specify the stripe width for a
273 RAID device or striped logical volume. The value is
274 expressed as a multiplier of the stripe unit, usu‐
275 ally the same as the number of stripe members in the
276 logical volume configuration, or data disks in a
277 RAID device.
278 When a filesystem is created on a logical volume
280 device, mkfs.xfs will automatically query the logi‐
281 cal volume for appropriate sunit and swidth values.
282 noalign
284 This option disables automatic geometry detection
285 and creates the filesystem without stripe geometry
286 alignment even if the underlying storage device pro‐
287 vides this information.
288 rtinherit=value
290 If set, all inodes created by mkfs.xfs will be cre‐
291 ated with the realtime flag set. Directories will
292 pass on this flag to newly created children.
293 projinherit=value
295 All inodes created by mkfs.xfs will be assigned this
296 project quota id. Directories will pass on the
297 project id to newly created children.
298 extszinherit=value
300 All inodes created by mkfs.xfs will have this extent
301 size hint applied. The value must be provided in
302 units of filesystem blocks. Directories will pass
303 on this hint to newly created children.
304 -f Force overwrite when an existing filesystem is detected on the
306 device. By default, mkfs.xfs will not write to the device if it
307 suspects that there is a filesystem or partition table on the
308 device already.
309 -i inode_options
311 This option specifies the inode size of the filesystem, and
312 other inode allocation parameters. The XFS inode contains a
313 fixed-size part and a variable-size part. The variable-size
314 part, whose size is affected by this option, can contain: direc‐
315 tory data, for small directories; attribute data, for small
316 attribute sets; symbolic link data, for small symbolic links;
317 the extent list for the file, for files with a small number of
318 extents; and the root of a tree describing the location of
319 extents for the file, for files with a large number of extents.
320 The valid inode_options are:
322 size=value | perblock=value
324 The inode size is specified either as a value in
325 bytes with size= or as the number fitting in a
326 filesystem block with perblock=. The minimum (and
327 default) value is 256 bytes without crc, 512 bytes
328 with crc enabled. The maximum value is 2048 (2 KiB)
329 subject to the restriction that the inode size can‐
330 not exceed one half of the filesystem block size.
331 XFS uses 64-bit inode numbers internally; however,
333 the number of significant bits in an inode number is
334 affected by filesystem geometry. In practice,
335 filesystem size and inode size are the predominant
336 factors. The Linux kernel (on 32 bit hardware plat‐
337 forms) and most applications cannot currently handle
338 inode numbers greater than 32 significant bits, so
339 if no inode size is given on the command line,
340 mkfs.xfs will attempt to choose a size such that
341 inode numbers will be < 32 bits. If an inode size
342 is specified, or if a filesystem is sufficiently
343 large, mkfs.xfs will warn if this will create inode
344 numbers > 32 significant bits.
345 maxpct=value
347 This specifies the maximum percentage of space in
348 the filesystem that can be allocated to inodes. The
349 default value is 25% for filesystems under 1TB, 5%
350 for filesystems under 50TB and 1% for filesystems
351 over 50TB.
352 In the default inode allocation mode, inode blocks
354 are chosen such that inode numbers will not exceed
355 32 bits, which restricts the inode blocks to the
356 lower portion of the filesystem. The data block
357 allocator will avoid these low blocks to accommodate
358 the specified maxpct, so a high value may result in
359 a filesystem with nothing but inodes in a signifi‐
360 cant portion of the lower blocks of the filesystem.
361 (This restriction is not present when the filesystem
362 is mounted with the inode64 option on 64-bit plat‐
363 forms).
364 Setting the value to 0 means that essentially all of
366 the filesystem can become inode blocks, subject to
367 inode32 restrictions.
368 This value can be modified with xfs_growfs(8).
370 align[=value]
372 This is used to specify that inode allocation is or
373 is not aligned. The value is either 0 or 1, with 1
374 signifying that inodes are allocated aligned. If
375 the value is omitted, 1 is assumed. The default is
376 that inodes are aligned. Aligned inode access is
377 normally more efficient than unaligned access;
378 alignment must be established at the time the
379 filesystem is created, since inodes are allocated at
380 that time. This option can be used to turn off
381 inode alignment when the filesystem needs to be
382 mountable by a version of IRIX that does not have
383 the inode alignment feature (any release of IRIX
384 before 6.2, and IRIX 6.2 without XFS patches).
385 attr=value
387 This is used to specify the version of extended
388 attribute inline allocation policy to be used. By
389 default, this is 2, which uses an efficient algo‐
390 rithm for managing the available inline inode space
391 between attribute and extent data.
392 The previous version 1, which has fixed regions for
394 attribute and extent data, is kept for backwards
395 compatibility with kernels older than version
396 2.6.16.
397 projid32bit[=value]
399 This is used to enable 32bit quota project identi‐
400 fiers. The value is either 0 or 1, with 1 signifying
401 that 32bit projid are to be enabled. If the value
402 is omitted, 1 is assumed. (This default changed in
403 release version 3.2.0.)
404 sparse[=value]
406 Enable sparse inode chunk allocation. The value is
407 either 0 or 1, with 1 signifying that sparse alloca‐
408 tion is enabled. If the value is omitted, 1 is
409 assumed. Sparse inode allocation is disabled by
410 default. This feature is only available for filesys‐
411 tems formatted with -m crc=1.
412 When enabled, sparse inode allocation allows the
414 filesystem to allocate smaller than the standard
415 64-inode chunk when free space is severely limited.
416 This feature is useful for filesystems that might
417 fragment free space over time such that no free
418 extents are large enough to accommodate a chunk of
419 64 inodes. Without this feature enabled, inode allo‐
420 cations can fail with out of space errors under
421 severe fragmented free space conditions.
422 -l log_section_options
424 These options specify the location, size, and other parameters
425 of the log section of the filesystem. The valid log_sec‐
426 tion_options are:
427 agnum=value
429 If the log is internal, allocate it in this AG.
430 internal[=value]
432 This is used to specify that the log section is a
433 piece of the data section instead of being another
434 device or logical volume. The value is either 0 or
435 1, with 1 signifying that the log is internal. If
436 the value is omitted, 1 is assumed.
437 logdev=device
439 This is used to specify that the log section should
440 reside on the device separate from the data section.
441 The internal=1 and logdev options are mutually
442 exclusive.
443 size=value
445 This is used to specify the size of the log section.
446 If the log is contained within the data section and
448 size isn't specified, mkfs.xfs will try to select a
449 suitable log size depending on the size of the
450 filesystem. The actual logsize depends on the
451 filesystem block size and the directory block size.
452 Otherwise, the size suboption is only needed if the
454 log section of the filesystem should occupy less
455 space than the size of the special file. The value
456 is specified in bytes or blocks, with a b suffix
457 meaning multiplication by the filesystem block size,
458 as described above. The overriding minimum value for
459 size is 512 blocks. With some combinations of
460 filesystem block size, inode size, and directory
461 block size, the minimum log size is larger than 512
462 blocks.
463 version=value
465 This specifies the version of the log. The current
466 default is 2, which allows for larger log buffer
467 sizes, as well as supporting stripe-aligned log
468 writes (see the sunit and su options, below).
469 The previous version 1, which is limited to 32k log
471 buffers and does not support stripe-aligned writes,
472 is kept for backwards compatibility with very old
473 2.4 kernels.
474 sunit=value
476 This specifies the alignment to be used for log
477 writes. The value has to be specified in 512-byte
478 block units. Use the su suboption to specify the log
479 stripe unit size in bytes. Log writes will be
480 aligned on this boundary, and rounded up to this
481 boundary. This gives major improvements in perfor‐
482 mance on some configurations such as software RAID5
483 when the sunit is specified as the filesystem block
484 size. The equivalent byte value must be a multiple
485 of the filesystem block size. Version 2 logs are
486 automatically selected if the log sunit suboption is
487 specified.
488 The su suboption is an alternative to using sunit.
490 su=value
492 This is used to specify the log stripe. The value
493 has to be specified in bytes, (usually using the s
494 or b suffixes). This value must be a multiple of the
495 filesystem block size. Version 2 logs are automati‐
496 cally selected if the log su suboption is specified.
497 lazy-count=value
499 This changes the method of logging various persis‐
500 tent counters in the superblock. Under metadata
501 intensive workloads, these counters are updated and
502 logged frequently enough that the superblock updates
503 become a serialization point in the filesystem. The
504 value can be either 0 or 1.
505 With lazy-count=1, the superblock is not modified or
507 logged on every change of the persistent counters.
508 Instead, enough information is kept in other parts
509 of the filesystem to be able to maintain the persis‐
510 tent counter values without needed to keep them in
511 the superblock. This gives significant improvements
512 in performance on some configurations. The default
513 value is 1 (on) so you must specify lazy-count=0 if
514 you want to disable this feature for older kernels
515 which don't support it.
516 -n naming_options
518 These options specify the version and size parameters for the
519 naming (directory) area of the filesystem. The valid nam‐
520 ing_options are:
521 size=value
523 The directory block size is specified with a value
524 in bytes. The block size must be a power of 2 and
525 cannot be less than the filesystem block size. The
526 default size value for version 2 directories is 4096
527 bytes (4 KiB), unless the filesystem block size is
528 larger than 4096, in which case the default value is
529 the filesystem block size. For version 1 directo‐
530 ries the block size is the same as the filesystem
531 block size.
532 version=value
534 The naming (directory) version value can be either 2
535 or 'ci', defaulting to 2 if unspecified. With ver‐
536 sion 2 directories, the directory block size can be
537 any power of 2 size from the filesystem block size
538 up to 65536.
539 The version=ci option enables ASCII only case-insen‐
541 sitive filename lookup and version 2 directories.
542 Filenames are case-preserving, that is, the names
543 are stored in directories using the case they were
544 created with.
545 Note: Version 1 directories are not supported.
547 ftype=value
549 This feature allows the inode type to be stored in
550 the directory structure so that the readdir(3) and
551 getdents(2) do not need to look up the inode to
552 determine the inode type.
553 The value is either 0 or 1, with 1 signifying that
555 filetype information will be stored in the directory
556 structure. The default value is 1.
557 When CRCs are enabled (the default), the ftype func‐
559 tionality is always enabled, and cannot be turned
560 off.
561 -p protofile
563 If the optional -p protofile argument is given, mkfs.xfs uses
564 protofile as a prototype file and takes its directions from that
565 file. The blocks and inodes specifiers in the protofile are
566 provided for backwards compatibility, but are otherwise unused.
567 The syntax of the protofile is defined by a number of tokens
568 separated by spaces or newlines. Note that the line numbers are
569 not part of the syntax but are meant to help you in the follow‐
570 ing discussion of the file contents.
571 1 /stand/diskboot
573 2 4872 110
574 3 d--777 3 1
575 4 usr d--777 3 1
576 5 sh ---755 3 1 /bin/sh
577 6 ken d--755 6 1
578 7 $
579 8 b0 b--644 3 1 0 0
580 9 c0 c--644 3 1 0 0
581 10 fifo p--644 3 1
582 11 slink l--644 3 1 /a/symbolic/link
583 12 : This is a comment line
584 13 $
585 14 $
586 Line 1 is a dummy string. (It was formerly the bootfilename.)
588 It is present for backward compatibility; boot blocks are not
589 used on SGI systems.
590 Note that some string of characters must be present as the first
592 line of the proto file to cause it to be parsed correctly; the
593 value of this string is immaterial since it is ignored.
594 Line 2 contains two numeric values (formerly the numbers of
596 blocks and inodes). These are also merely for backward compati‐
597 bility: two numeric values must appear at this point for the
598 proto file to be correctly parsed, but their values are immate‐
599 rial since they are ignored.
600 The lines 3 through 11 specify the files and directories you
602 want to include in this filesystem. Line 3 defines the root
603 directory. Other directories and files that you want in the
604 filesystem are indicated by lines 4 through 6 and lines 8
605 through 10. Line 11 contains symbolic link syntax.
606 Notice the dollar sign ($) syntax on line 7. This syntax directs
608 the mkfs.xfs command to terminate the branch of the filesystem
609 it is currently on and then continue from the directory speci‐
610 fied by the next line, in this case line 8. It must be the last
611 character on a line. The colon on line 12 introduces a comment;
612 all characters up until the following newline are ignored. Note
613 that this means you cannot have a file in a prototype file whose
614 name contains a colon. The $ on lines 13 and 14 end the
615 process, since no additional specifications follow.
616 File specifications provide the following:
618 * file mode
620 * user ID
621 * group ID
622 * the file's beginning contents
623 A 6-character string defines the mode for a file. The first
625 character of this string defines the file type. The character
626 range for this first character is -bcdpl. A file may be a regu‐
627 lar file, a block special file, a character special file, direc‐
628 tory files, named pipes (first-in, first out files), and sym‐
629 bolic links. The second character of the mode string is used to
630 specify setuserID mode, in which case it is u. If setuserID
631 mode is not specified, the second character is -. The third
632 character of the mode string is used to specify the setgroupID
633 mode, in which case it is g. If setgroupID mode is not speci‐
634 fied, the third character is -. The remaining characters of the
635 mode string are a three digit octal number. This octal number
636 defines the owner, group, and other read, write, and execute
637 permissions for the file, respectively. For more information on
638 file permissions, see the chmod(1) command.
639 Following the mode character string are two decimal number
641 tokens that specify the user and group IDs of the file's owner.
642 In a regular file, the next token specifies the pathname from
644 which the contents and size of the file are copied. In a block
645 or character special file, the next token are two decimal num‐
646 bers that specify the major and minor device numbers. When a
647 file is a symbolic link, the next token specifies the contents
648 of the link.
649 When the file is a directory, the mkfs.xfs command creates the
651 entries dot (.) and dot-dot (..) and then reads the list of
652 names and file specifications in a recursive manner for all of
653 the entries in the directory. A scan of the protofile is always
654 terminated with the dollar ( $ ) token.
655 -q Quiet option. Normally mkfs.xfs prints the parameters of the
657 filesystem to be constructed; the -q flag suppresses this.
658 -r realtime_section_options
660 These options specify the location, size, and other parameters
661 of the real-time section of the filesystem. The valid real‐
662 time_section_options are:
663 rtdev=device
665 This is used to specify the device which should con‐
666 tain the real-time section of the filesystem. The
667 suboption value is the name of a block device.
668 extsize=value
670 This is used to specify the size of the blocks in
671 the real-time section of the filesystem. This value
672 must be a multiple of the filesystem block size. The
673 minimum allowed size is the filesystem block size or
674 4 KiB (whichever is larger); the default size is the
675 stripe width for striped volumes or 64 KiB for non-
676 striped volumes; the maximum allowed size is 1 GiB.
677 The real-time extent size should be carefully chosen
678 to match the parameters of the physical media used.
679 size=value
681 This is used to specify the size of the real-time
682 section. This suboption is only needed if the real-
683 time section of the filesystem should occupy less
684 space than the size of the partition or logical vol‐
685 ume containing the section.
686 noalign
688 This option disables stripe size detection, enforc‐
689 ing a realtime device with no stripe geometry.
690 -s sector_size_options
692 This option specifies the fundamental sector size of the
693 filesystem. The valid sector_size_option is:
694 size=value
696 The sector size is specified with a value in bytes.
697 The default sector_size is 512 bytes. The minimum
698 value for sector size is 512; the maximum is 32768
699 (32 KiB). The sector_size must be a power of 2 size
700 and cannot be made larger than the filesystem block
701 size.
702 To specify any options on the command line in units
704 of sectors, this option must be specified first so
705 that the sector size is applied consistently to all
706 options.
707 -L label
709 Set the filesystem label. XFS filesystem labels can be at most
710 12 characters long; if label is longer than 12 characters,
711 mkfs.xfs will not proceed with creating the filesystem. Refer
712 to the mount(8) and xfs_admin(8) manual entries for additional
713 information.
714 -N Causes the file system parameters to be printed out without
716 really creating the file system.
717 -K Do not attempt to discard blocks at mkfs time.
719 -V Prints the version number and exits.
721
723 xfs(5), mkfs(8), mount(8), xfs_info(8), xfs_admin(8).
724
726 With a prototype file, it is not possible to specify hard links.
727 mkfs.xfs(8)