| blob | 9e9ff764324575e8231b4c60fbd3eef4a1b23ff8 |
1 .\" Copyright (c) 1987, 1988, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
3 .\"
4 .\" This code is derived from software contributed to Berkeley by
5 .\" Symmetric Computer Systems.
6 .\"
7 .\" Redistribution and use in source and binary forms, with or without
8 .\" modification, are permitted provided that the following conditions
9 .\" are met:
10 .\" 1. Redistributions of source code must retain the above copyright
11 .\" notice, this list of conditions and the following disclaimer.
12 .\" 2. Redistributions in binary form must reproduce the above copyright
13 .\" notice, this list of conditions and the following disclaimer in the
14 .\" documentation and/or other materials provided with the distribution.
15 .\" 3. All advertising materials mentioning features or use of this software
16 .\" must display the following acknowledgment:
17 .\" This product includes software developed by the University of
18 .\" California, Berkeley and its contributors.
19 .\" 4. Neither the name of the University nor the names of its contributors
20 .\" may be used to endorse or promote products derived from this software
21 .\" without specific prior written permission.
22 .\"
23 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 .\" SUCH DAMAGE.
34 .\"
35 .\" @(#)disklabel.8 8.2 (Berkeley) 4/19/94
36 .\" $FreeBSD: src/sbin/disklabel/disklabel.8,v 1.15.2.22 2003/04/17 17:56:34 trhodes Exp $
37 .\" $DragonFly: src/sbin/disklabel64/disklabel64.8,v 1.13 2008/09/16 20:45:36 thomas Exp $
38 .\"
39 .Dd September 28, 2009
40 .Dt DISKLABEL64 8
41 .Os
42 .Sh NAME
43 .Nm disklabel64
44 .Nd read and write 64 bit disk pack label
45 .Sh SYNOPSIS
46 .Nm
47 .Op Fl r
48 .Ar disk
49 .Nm
50 .Fl w
51 .Op Fl r
52 .Op Fl n
53 .Ar disk Ar disktype Ns / Ns Cm auto
54 .Oo Ar packid Oc
55 .Nm
56 .Fl e
57 .Op Fl r
58 .Op Fl n
59 .Ar disk
60 .Nm
61 .Fl R
62 .Op Fl r
63 .Op Fl n
64 .Ar disk Ar protofile
65 .Nm
66 .Op Fl NW
67 .Ar disk
68 .Pp
69 .Nm
70 .Fl B
71 .Oo
72 .Fl b Ar boot1
73 .Fl s Ar boot2
74 .Oc
75 .Ar disk
76 .Oo Ar disktype Ns / Ns Cm auto Oc
77 .Nm
78 .Fl w
79 .Fl B
80 .Op Fl n
81 .Oo
82 .Fl b Ar boot1
83 .Fl s Ar boot2
84 .Oc
85 .Ar disk Ar disktype Ns / Ns Cm auto
86 .Oo Ar packid Oc
87 .Nm
88 .Fl R
89 .Fl B
90 .Op Fl n
91 .Oo
92 .Fl b Ar boot1
93 .Fl s Ar boot2
94 .Oc
95 .Ar disk Ar protofile
96 .Oo Ar disktype Ns / Ns Cm auto Oc
97 .Sh DESCRIPTION
98 The
99 .Nm
100 utility
101 installs, examines or modifies a 64 bit label on a disk drive or pack.
102 When writing
103 the label, it can be used to change the drive identification, the disk
104 partitions on the drive, or to replace a damaged label.
105 There are several forms
106 of the command that read (display), install or edit the label on a disk.
107 In
108 addition,
109 .Nm
110 can install bootstrap code.
111 .Ss Raw or in-core label
112 The disk label resides close to or at the beginning of each disk slice.
113 For faster access, the kernel maintains a copy in core at all times.
114 By
115 default, most forms of the
116 .Nm
117 command access the in-core copy of the label.
118 To access the raw (on-disk)
119 copy, use the
120 .Fl r
121 option.
122 This option allows a label to be installed on a disk without kernel
123 support for a label, such as when labels are first installed on a system; it
124 must be used when first installing a label on a disk.
125 The specific effect of
126 .Fl r
127 is described under each command.
128 .Ss Disk device name
129 All
130 .Nm
131 forms require a disk device name, which should always be the raw
132 device name representing the disk or slice.
133 .Dx
134 uses the following scheme for slice numbering:
135 If the disk doesn't use GPT (typically laid out by
136 .Xr gpt 8 ) ,
137 but e.g.\& MBR (typically laid out by
138 .Xr fdisk 8 ) ,
139 then slice 0, e.g.\&
140 .Pa da0s0 ,
141 represents the entire disk regardless of any DOS partitioning.
142 Slice 0 is called the compatibility slice,
143 and slice 1 and onward, e.g.\&
144 .Pa da0s1 ,
145 represents a
146 .Bx
147 slice.
148 If the disk does use GPT, then all slices are
149 .Bx
150 slices, slice 0 isn't special, it is just the first slice on the disk.
151 You do not have to include the
152 .Pa /dev/
153 path prefix when specifying the device.
154 The
155 .Nm
156 utility will automatically prepend it.
157 .Ss Reading the disk label
158 To examine the label on a disk drive, use
159 .Nm
160 without options:
161 .Pp
162 .Nm
163 .Op Fl r
164 .Ar disk
165 .Pp
166 .Ar disk
167 represents the raw disk in question, and may be in the form
168 .Pa da0s1
169 or
170 .Pa /dev/da0s1 .
171 It will display all of the parameters associated with the drive and its
172 partition layout.
173 Unless the
174 .Fl r
175 flag is given,
176 the kernel's in-core copy of the label is displayed;
177 if the disk has no label, or the partition types on the disk are incorrect,
178 the kernel may have constructed or modified the label.
179 If the
180 .Fl r
181 flag is given,
182 .Nm
183 reads the label from the raw disk and displays it.
184 Both versions are usually
185 identical except in the case where a label has not yet been initialized or
186 is corrupt.
187 .Ss Writing a standard label
188 To write a standard label, use the form
189 .Pp
190 .Nm
191 .Fl w
192 .Op Fl r
193 .Op Fl n
194 .Ar disk Ar disktype Ns / Ns Cm auto
195 .Oo Ar packid Oc
196 .Pp
197 The required arguments to
198 .Nm
199 are the drive to be labeled and the drive type as described in the
200 .Xr disktab 5
201 file.
202 The drive parameters and partitions are taken from that file.
203 If
204 different disks of the same physical type are to have different partitions, it
205 will be necessary to have separate disktab entries describing each, or to edit
206 the label after installation as described below.
207 The optional argument is a
208 pack identification string, up to 16 characters long.
209 The pack id must be
210 quoted if it contains blanks.
211 .Pp
212 If the
213 .Fl n
214 flag is given, no data will be written to the device, and instead the
215 disklabel that would have been written will be printed to stdout.
216 .Pp
217 If the
218 .Fl r
219 flag is given, the disk sectors containing the label and bootstrap
220 will be written directly.
221 A side-effect of this is that any existing bootstrap code will be overwritten
222 and the disk rendered unbootable.
223 See the boot options below for a method of
224 writing the label and the bootstrap at the same time.
225 If
226 .Fl r
227 is not specified,
228 the existing label will be updated via the in-core copy and any bootstrap
229 code will be unaffected.
230 If the disk does not already have a label, the
231 .Fl r
232 flag must be used.
233 In either case, the kernel's in-core label is replaced.
234 .Pp
235 For a virgin disk that is not known to
236 .Xr disktab 5 ,
237 .Ar disktype
238 can be specified as
239 .Cm auto .
240 In this case, the driver is requested to produce a virgin label for the
241 disk.
242 This might or might not be successful, depending on whether the
243 driver for the disk is able to get the required data without reading
244 anything from the disk at all.
245 It will likely succeed for all SCSI
246 disks, most IDE disks, and vnode devices.
247 Writing a label to the
248 disk is the only supported operation, and the
249 .Ar disk
250 itself must be provided as the canonical name, i.e.\& not as a full
251 path name.
252 .Pp
253 For most harddisks, a label based on percentages for most partitions (and
254 one partition with a size of
255 .Ql * )
256 will produce a reasonable configuration.
257 .Pp
258 PC-based systems have special requirements in order for the BIOS to properly
259 recognize a
260 .Dx
261 disklabel.
262 Older systems may require what is known as a
263 .Dq dangerously dedicated
264 disklabel, which creates a fake DOS partition to work around problems older
265 BIOSes have with modern disk geometries.
266 On newer systems you generally want
267 to create a normal DOS partition using
268 .Ar fdisk
269 and then create a
270 .Dx
271 disklabel within that slice.
272 This is described
273 later on in this page.
274 .Pp
275 Installing a new disklabel does not in of itself allow your system to boot
276 a kernel using that label.
277 You must also install boot blocks, which is
278 described later on in this manual page.
279 .Ss Editing an existing disk label
280 To edit an existing disk label, use the form
281 .Pp
282 .Nm
283 .Fl e
284 .Op Fl r
285 .Op Fl n
286 .Ar disk
287 .Pp
288 This command reads the label from the in-core kernel copy, or directly from the
289 disk if the
290 .Fl r
291 flag is also specified.
292 The label is written to a file in ASCII and then
293 supplied to an editor for changes.
294 If no editor is specified in an
295 .Ev EDITOR
296 environment variable,
297 .Xr vi 1
298 is used.
299 When the editor terminates, the label file is used to rewrite the disk label.
300 Existing bootstrap code is unchanged regardless of whether
301 .Fl r
302 was specified.
303 If
304 .Fl n
305 is specified, no data will be written to the device, and instead the
306 disklabel that would have been written will be printed to stdout.
307 This is
308 useful to see how a partitioning scheme will work out for a specific disk.
309 .Ss Restoring a disk label from a file
310 To restore a disk label from a file, use the form
311 .Pp
312 .Nm
313 .Fl R
314 .Op Fl r
315 .Op Fl n
316 .Ar disk Ar protofile
317 .Pp
318 .Nm
319 is capable of restoring a disk label that was previously saved in a file
320 in ASCII format.
321 The prototype file used to create the label should be in the same format
322 as that produced when reading or editing a label.
323 Comments are delimited by
324 .Ql #
325 and newline.
326 As when writing a new label, any existing bootstrap code will be
327 clobbered if
328 .Fl r
329 is specified and will be unaffected otherwise.
330 See the boot options below for a
331 method of restoring the label and writing the bootstrap at the same time.
332 If
333 .Fl n
334 is used, no data will be written to the device, and instead the
335 disklabel that would have been written will be printed to stdout.
336 This is
337 useful to see how a partitioning scheme will work out for a specific disk.
338 .Ss Enabling and disabling writing to the disk label area
339 By default, it is not possible to write to the disk label area at the beginning
340 of a disk.
341 The disk driver arranges for
342 .Xr write 2
343 and similar system calls
344 to return
345 .Er EROFS
346 on any attempt to do so.
347 If you need
348 to write to this area (for example, to obliterate the label), use the form
349 .Pp
350 .Nm
351 .Fl W
352 .Ar disk
353 .Pp
354 To disallow writing to the label area after previously allowing it,
355 use the command
356 .Pp
357 .Nm
358 .Fl N
359 .Ar disk
360 .Ss Installing bootstraps
361 The final three forms of
362 .Nm
363 are used to install bootstrap code, which allows boot from a
364 .Xr HAMMER 5
365 or
366 .Xr UFS 5
367 file system.
368 If you are creating a
369 .Dq dangerously-dedicated
370 slice for compatibility with older PC systems,
371 you generally want to specify the compatibility slice, such as
372 .Pa da0s0 .
373 If you are creating a label within an existing DOS slice,
374 you should specify
375 the slice name such as
376 .Pa da0s1 .
377 Making a slice bootable can be tricky.
378 If you are using a normal DOS
379 slice you typically install (or leave) a standard MBR on the base disk and
380 then install the
381 .Dx
382 bootblocks in the slice.
383 .Pp
384 .Nm
385 .Fl B
386 .Oo
387 .Fl b Ar boot1
388 .Fl s Ar boot2
389 .Oc
390 .Ar disk
391 .Oo Ar disktype Ns / Ns Cm auto Oc
392 .Pp
393 This form installs the bootstrap only.
394 It does not change the disk label.
395 You should never use this command on the compatibility slice unless you
396 intend to create a
397 .Dq dangerously-dedicated
398 disk, such as
399 .Ar da0s0 .
400 This command is typically run on a
401 .Bx
402 slice such as
403 .Ar da0s1 .
404 .Pp
405 .Nm
406 .Fl w
407 .Fl B
408 .Op Fl n
409 .Oo
410 .Fl b Ar boot1
411 .Fl s Ar boot2
412 .Oc
413 .Ar disk Ar disktype Ns / Ns Cm auto
414 .Oo Ar packid Oc
415 .Pp
416 This form corresponds to the
417 .Dq write label
418 command described above.
419 In addition to writing a new volume label, it also installs the bootstrap.
420 If run on the compatibility slice this command will create a
421 .Dq dangerously-dedicated
422 label.
423 This command is normally run on a
424 .Bx
425 slice rather than the compatibility slice.
426 If
427 .Fl n
428 is used, no data will be written to the device, and instead the
429 disklabel that would have been written will be printed to stdout.
430 .Pp
431 .Nm
432 .Fl R
433 .Fl B
434 .Op Fl n
435 .Oo
436 .Fl b Ar boot1
437 .Fl s Ar boot2
438 .Oc
439 .Ar disk Ar protofile
440 .Oo Ar disktype Ns / Ns Cm auto Oc
441 .Pp
442 This form corresponds to the
443 .Dq restore label
444 command described above.
445 In addition to restoring the volume label, it also installs the bootstrap.
446 If run on the compatibility slice this command will create a
447 .Dq dangerously-dedicated
448 label.
449 This command is normally run on a
450 .Bx
451 slice rather than the compatibility
452 slice.
453 .Pp
454 The bootstrap commands always access the disk directly,
455 so it is not necessary to specify the
456 .Fl r
457 flag.
458 If
459 .Fl n
460 is used, no data will be written to the device, and instead the
461 disklabel that would have been written will be printed to stdout.
462 .Pp
463 The bootstrap code is comprised of two boot programs.
464 Specify the name of the
465 boot programs to be installed in one of these ways:
466 .Bl -enum
467 .It
468 Specify the names explicitly with the
469 .Fl b
470 and
471 .Fl s
472 flags.
473 .Fl b
474 indicates the primary boot program and
475 .Fl s
476 the secondary boot program.
477 The boot programs are normally located in
478 .Pa /boot .
479 .It
480 If the
481 .Fl b
482 and
483 .Fl s
484 flags are not specified, but
485 .Ar disktype
486 was specified, the names of the programs are taken from the
487 .Dq b0
488 and
489 .Dq b1
490 parameters of the
491 .Xr disktab 5
492 entry for the disk if the disktab entry exists and includes those parameters.
493 .It
494 Otherwise, the default boot image names are used:
495 .Pa /boot/boot1_64
496 and
497 .Pa /boot/boot2_64
498 for the standard stage1 and stage2 boot images.
499 .El
500 .Ss Initializing/Formatting a bootable disk from scratch
501 To initialize a disk from scratch the following sequence is recommended.
502 Please note that this will wipe everything that was previously on the disk,
503 including any
504 .No non- Ns Dx
505 slices.
506 .Bl -enum
507 .It
508 Use
509 .Xr gpt 8
510 or
511 .Xr fdisk 8
512 to initialize the hard disk, and create a GPT or MBR slice table,
513 referred to as the
514 .Dq "partition table"
515 in
516 .Tn DOS .
517 .It
518 Use
519 .Nm
520 or
521 .Xr disklabel 8
522 to define partitions on
523 .Dx
524 slices created in the previous step.
525 .It
526 Finally use
527 .Xr newfs_hammer 8
528 or
529 .Xr newfs 8
530 to create file systems on new partitions.
531 .El
532 .Pp
533 A typical partitioning scheme would be to have an
534 .Ql a
535 partition
536 of approximately 512MB to hold the root file system, a
537 .Ql b
538 partition for
539 swap (usually 4GB), a
540 .Ql d
541 partition for
542 .Pa /var
543 (usually 2GB), an
544 .Ql e
545 partition for
546 .Pa /var/tmp
547 (usually 2GB), an
548 .Ql f
549 partition for
550 .Pa /usr
551 (usually around 4GB),
552 and finally a
553 .Ql g
554 partition for
555 .Pa /home
556 (usually all remaining space).
557 If you are tight on space all sizes can be halved.
558 Your mileage may vary.
559 .Pp
560 .Dl "gpt create da0"
561 .Dl "gpt add da0"
562 .Dl "disklabel64 -B -r -w da0s0 auto"
563 .Dl "disklabel64 -e da0s0"
564 .Sh FILES
565 .Bl -tag -width ".Pa /boot/boot2_64" -compact
566 .It Pa /boot/boot1_64
567 Default stage1 boot image.
568 .It Pa /boot/boot2_64
569 Default stage2 boot image.
570 .It Pa /etc/disktab
571 Disk description file.
572 .El
573 .Sh SAVED FILE FORMAT
574 The
575 .Nm
576 utility uses an
577 .Tn ASCII
578 version of the label when examining, editing, or restoring a disk label.
579 The format is:
580 .Bd -literal -offset 4n
581 # /dev/ad4s4:
582 #
583 # Informational fields calculated from the above
584 # All byte equivalent offsets must be aligned
585 #
586 # boot space: 32768 bytes
587 # data space: 121790552 blocks # 118936.09 MB (124713525248 bytes)
588 #
589 diskid: 5e3ef4db-4e24-11dd-8318-010e0cd0bad1
590 label:
591 boot2 data base: 0x000000001000
592 partitions data base: 0x000000009000
593 partitions data stop: 0x001d0981f000
594 backup label: 0x001d0981f000
595 total size: 0x001d09820000 # 118936.12 MB
596 alignment: 4096
597 display block size: 1024 # for partition display only
599 16 partitions:
600 # size offset fstype fsuuid
601 a: 524288 0 4.2BSD # 512.000MB
602 b: 4194304 524288 swap # 4096.000MB
603 d: 2097152 4718592 4.2BSD # 2048.000MB
604 e: 2097152 6815744 4.2BSD # 2048.000MB
605 f: 4194304 8912896 4.2BSD # 4096.000MB
606 g: 4194304 13107200 4.2BSD # 4096.000MB
607 h: 94003288 17301504 HAMMER # 91800.086MB
608 i: 5242880 111304792 ccd # 5120.000MB
609 j: 5242880 116547672 vinum # 5120.000MB
610 a-stor_uuid: 4370efdb-4e25-11dd-8318-010e0cd0bad1
611 b-stor_uuid: 4370eff4-4e25-11dd-8318-010e0cd0bad1
612 d-stor_uuid: 4370f00b-4e25-11dd-8318-010e0cd0bad1
613 e-stor_uuid: 4370f024-4e25-11dd-8318-010e0cd0bad1
614 f-stor_uuid: 4370f03a-4e25-11dd-8318-010e0cd0bad1
615 g-stor_uuid: 4370f053-4e25-11dd-8318-010e0cd0bad1
616 h-stor_uuid: 4370f06a-4e25-11dd-8318-010e0cd0bad1
617 i-stor_uuid: 4370f083-4e25-11dd-8318-010e0cd0bad1
618 j-stor_uuid: 4370f099-4e25-11dd-8318-010e0cd0bad1
619 .Ed
620 .Pp
621 Lines starting with a
622 .Ql #
623 mark are comments.
624 The specifications which can be changed are:
625 .Bl -inset
626 .It Ar label
627 is an optional label, set by the
628 .Ar packid
629 option when writing a label.
630 .It Ar "the partition table"
631 is the
632 .Ux
633 partition table, not the
634 .Tn DOS
635 partition table described in
636 .Xr fdisk 8 .
637 .El
638 .Pp
639 The partition table can have up to 16 entries.
640 It contains the following information:
641 .Bl -tag -width indent
642 .It Ar #
643 The partition identifier is a single letter in the range
644 .Ql a
645 to
646 .Ql p .
647 .It Ar size
648 The size of the partition in sectors,
649 .Cm K
650 (kilobytes - 1024),
651 .Cm M
652 (megabytes - 1024*1024),
653 .Cm G
654 (gigabytes - 1024*1024*1024),
655 .Cm %
656 (percentage of free space
657 .Em after
658 removing any fixed-size partitions),
659 .Cm *
660 (all remaining free space
661 .Em after
662 fixed-size and percentage partitions).
663 Lowercase versions of
664 .Cm K , M ,
665 and
666 .Cm G
667 are allowed.
668 Size and type should be specified without any spaces between them.
669 .Pp
670 Example: 2097152, 1G, 1024M and 1048576K are all the same size
671 (assuming 512-byte sectors).
672 .It Ar offset
673 The offset of the start of the partition from the beginning of the
674 drive in sectors, or
675 .Cm *
676 to have
677 .Nm
678 calculate the correct offset to use (the end of the previous partition plus
679 one.
680 .It Ar fstype
681 Describes the purpose of the partition.
682 The example shows all currently used partition types.
683 For
684 .Xr UFS 5
685 file systems, use type
686 .Cm 4.2BSD .
687 For
688 .Xr HAMMER 5
689 file systems, use type
690 .Cm HAMMER .
691 For
692 .Xr ccd 4
693 partitions, use type
694 .Cm ccd .
695 For Vinum drives, use type
696 .Cm vinum .
697 Other common types are
698 .Cm swap
699 and
700 .Cm unused .
701 The
702 .Nm
703 utility
704 also knows about a number of other partition types,
705 none of which are in current use.
706 (See
707 .Dv fstypenames
708 in
709 .In sys/dtype.h
710 for more details).
711 .El
712 .Pp
713 The remainder of the line is a comment and shows the size of
714 the partition in MB.
715 .Sh EXAMPLES
716 .Dl "disklabel64 da0s1"
717 .Pp
718 Display the in-core label for the first slice of the
719 .Pa da0
720 disk, as obtained via
721 .Pa /dev/da0s1 .
722 (If the disk is
723 .Dq dangerously-dedicated ,
724 the compatibility slice name should be specified, such as
725 .Pa da0s0 . )
726 .Pp
727 .Dl "disklabel64 da0s1 > savedlabel"
728 .Pp
729 Save the in-core label for
730 .Pa da0s1
731 into the file
732 .Pa savedlabel .
733 This file can be used with the
734 .Fl R
735 option to restore the label at a later date.
736 .Pp
737 .Dl "disklabel64 -w -r /dev/da0s1 da2212 foo"
738 .Pp
739 Create a label for
740 .Pa da0s1
741 based on information for
742 .Dq da2212
743 found in
744 .Pa /etc/disktab .
745 Any existing bootstrap code will be clobbered
746 and the disk rendered unbootable.
747 .Pp
748 .Dl "disklabel64 -e -r da0s1"
749 .Pp
750 Read the on-disk label for
751 .Pa da0s1 ,
752 edit it, and reinstall in-core as well as on-disk.
753 Existing bootstrap code is unaffected.
754 .Pp
755 .Dl "disklabel64 -e -r -n da0s1"
756 .Pp
757 Read the on-disk label for
758 .Pa da0s1 ,
759 edit it, and display what the new label would be (in sectors).
760 It does
761 .Em not
762 install the new label either in-core or on-disk.
763 .Pp
764 .Dl "disklabel64 -r -w da0s1 auto"
765 .Pp
766 Try to auto-detect the required information from
767 .Pa da0s1 ,
768 and write a new label to the disk.
769 Use another
770 .Nm Fl e
771 command to edit the partitioning information.
772 .Pp
773 .Dl "disklabel64 -R da0s1 savedlabel"
774 .Pp
775 Restore the on-disk and in-core label for
776 .Pa da0s1
777 from information in
778 .Pa savedlabel .
779 Existing bootstrap code is unaffected.
780 .Pp
781 .Dl "disklabel64 -R -n da0s1 label_layout"
782 .Pp
783 Display what the label would be for
784 .Pa da0s1
785 using the partition layout in
786 .Pa label_layout .
787 This is useful for determining how much space would be allotted for various
788 partitions with a labelling scheme using
789 .Cm % Ns -based
790 or
791 .Cm *
792 partition sizes.
793 .Pp
794 .Dl "disklabel64 -B da0s1"
795 .Pp
796 Install a new bootstrap on
797 .Pa da0s1 .
798 The boot code comes from
799 .Pa /boot/boot1_64
800 and possibly
801 .Pa /boot/boot2_64 .
802 On-disk and in-core labels are unchanged.
803 .Pp
804 .Dl "disklabel64 -w -B /dev/da0s1 -b newboot1 -s newboot2 da2212"
805 .Pp
806 Install a new label and bootstrap.
807 The label is derived from disktab information for
808 .Dq da2212
809 and installed both in-core and on-disk.
810 The bootstrap code comes from the files
811 .Pa newboot1
812 and
813 .Pa newboot2 .
814 .Pp
815 .Dl "dd if=/dev/zero of=/dev/da0 bs=512 count=32"
816 .Dl "fdisk -BI da0"
817 .Dl "dd if=/dev/zero of=/dev/da0s1 bs=512 count=32"
818 .Dl "disklabel64 -w -B da0s1 auto"
819 .Dl "disklabel64 -e da0s1"
820 .Pp
821 Completely wipe any prior information on the disk, creating a new bootable
822 disk with a DOS partition table containing one
823 .Dq whole-disk
824 slice.
825 Then
826 initialize the slice, then edit it to your needs.
827 The
828 .Pa dd
829 commands are optional, but may be necessary for some BIOSes to properly
830 recognize the disk.
831 .Pp
832 .Dl "disklabel64 -W da0s1"
833 .Dl "dd if=/dev/zero of=/dev/da0s1 bs=512 count=32"
834 .Dl "disklabel -r -w da0s1 auto"
835 .Dl "disklabel -N da0s1"
836 .Pp
837 Completely wipe any prior information on the slice,
838 changing label format to 32 bit.
839 The wiping is needed as
840 .Nm disklabel
841 and
842 .Nm ,
843 as a safety measure,
844 won't do any operations if label with other format is already installed.
845 .Pp
846 This is an example disklabel that uses some of the new partition size types
847 such as
848 .Cm % , M , G ,
849 and
850 .Cm * ,
851 which could be used as a source file for
852 .Pp
853 .Dl "disklabel64 -R ad0s1 new_label_file"
854 .Bd -literal -offset 4n
855 # /dev/ad4s4:
856 #
857 # Informational fields calculated from the above
858 # All byte equivalent offsets must be aligned
859 #
860 # boot space: 32768 bytes
861 # data space: 121790552 blocks # 118936.09 MB (124713525248 bytes)
862 #
863 diskid: b1db58a3-4e26-11dd-8318-010e0cd0bad1
864 label:
865 boot2 data base: 0x000000001000
866 partitions data base: 0x000000009000
867 partitions data stop: 0x001d0981f000
868 backup label: 0x001d0981f000
869 total size: 0x001d09820000 # 118936.12 MB
870 alignment: 4096
871 display block size: 1024 # for partition display only
873 16 partitions:
874 # size offset fstype fsuuid
875 a: 512M 0 4.2BSD
876 b: 4G * swap
877 d: 2G * 4.2BSD
878 e: 2048M * 4.2BSD
879 f: 4G * 4.2BSD
880 g: 4G * 4.2BSD
881 h: * * HAMMER
882 i: 5g * ccd
883 j: 5120m * vinum
884 .Ed
885 .Sh DIAGNOSTICS
886 The kernel device drivers will not allow the size of a disk partition
887 to be decreased or the offset of a partition to be changed while it is open.
888 Some device drivers create a label containing only a single large partition
889 if a disk is unlabeled; thus, the label must be written to the
890 .Ql a
891 partition of the disk while it is open.
892 This sometimes requires the desired
893 label to be set in two steps, the first one creating at least one other
894 partition, and the second setting the label on the new partition while
895 shrinking the
896 .Ql a
897 partition.
898 .Sh SEE ALSO
899 .Xr dd 1 ,
900 .Xr uuid 3 ,
901 .Xr ccd 4 ,
902 .Xr disklabel64 5 ,
903 .Xr disktab 5 ,
904 .Xr boot0cfg 8 ,
905 .Xr diskinfo 8 ,
906 .Xr disklabel 8 ,
907 .Xr fdisk 8 ,
908 .Xr gpt 8 ,
909 .Xr newfs 8 ,
910 .Xr newfs_hammer 8 ,
911 .Xr vinum 8
912 .Sh BUGS
913 For the i386 architecture, the primary bootstrap sector contains
914 an embedded
915 .Em fdisk
916 table.
917 The
918 .Nm
919 utility takes care to not clobber it when installing a bootstrap only
920 .Pq Fl B ,
921 or when editing an existing label
922 .Pq Fl e ,
923 but it unconditionally writes the primary bootstrap program onto
924 the disk for
925 .Fl w
926 or
927 .Fl R ,
928 thus replacing the
929 .Em fdisk
930 table by the dummy one in the bootstrap program.
931 This is only of
932 concern if the disk is fully dedicated, so that the
933 .Bx
934 disklabel
935 starts at absolute block 0 on the disk.
936 .Pp
937 The
938 .Nm
939 utility
940 does not perform all possible error checking.
941 Warning
942 .Em is
943 given if partitions
944 overlap; if an absolute offset does not match the expected offset; if a
945 partition runs past the end of the device; and a number of other errors; but
946 no warning is given if space remains unused.