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| 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/disklabel/disklabel.8,v 1.9 2006/05/26 19:39:38 swildner Exp $ |
| 38 | .\" |
| 39 | .Dd July 30, 1999 |
| 40 | .Dt DISKLABEL 8 |
| 41 | .Os |
| 42 | .Sh NAME |
| 43 | .Nm disklabel |
| 44 | .Nd read and write 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/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/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/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/auto Oc |
| 97 | .Sh DESCRIPTION |
| 98 | The |
| 99 | .Nm |
| 100 | utility |
| 101 | installs, examines or modifies the label on a disk drive or pack. When writing |
| 102 | the label, it can be used to change the drive identification, the disk |
| 103 | partitions on the drive, or to replace a damaged label. There are several forms |
| 104 | of the command that read (display), install or edit the label on a disk. In |
| 105 | addition, |
| 106 | .Nm |
| 107 | can install bootstrap code. |
| 108 | .Ss Raw or in-core label |
| 109 | The disk label resides close to or at the beginning of each disk slice. |
| 110 | For faster access, the kernel maintains a copy in core at all times. By |
| 111 | default, most forms of the |
| 112 | .Nm |
| 113 | command access the in-core copy of the label. To access the raw (on-disk) |
| 114 | copy, use the |
| 115 | .Fl r |
| 116 | option. This option allows a label to be installed on a disk without kernel |
| 117 | support for a label, such as when labels are first installed on a system; it |
| 118 | must be used when first installing a label on a disk. The specific effect of |
| 119 | .Fl r |
| 120 | is described under each command. |
| 121 | .Ss Disk device name |
| 122 | All |
| 123 | .Nm |
| 124 | forms require a disk device name, which should always be the raw |
| 125 | device name representing the disk or slice. For example |
| 126 | .Pa da0 |
| 127 | represents the entire disk regardless of any DOS partitioning, |
| 128 | and |
| 129 | .Pa da0s1 |
| 130 | represents a slice. Some devices, most notably |
| 131 | .Ar ccd , |
| 132 | require that the |
| 133 | .Dq whole-disk |
| 134 | (or |
| 135 | .Dq c ) |
| 136 | partition be specified. For example |
| 137 | .Pa ccd0c . |
| 138 | You do not have to include the |
| 139 | .Pa /dev/ |
| 140 | path prefix when specifying the device. |
| 141 | The |
| 142 | .Nm |
| 143 | utility will automatically prepend it. |
| 144 | .Ss Reading the disk label |
| 145 | To examine the label on a disk drive, use |
| 146 | .Nm |
| 147 | without options: |
| 148 | .Pp |
| 149 | .Nm |
| 150 | .Op Fl r |
| 151 | .Ar disk |
| 152 | .Pp |
| 153 | .Ar disk |
| 154 | represents the raw disk in question, and may be in the form |
| 155 | .Pa da0 |
| 156 | or |
| 157 | .Pa /dev/da0c . |
| 158 | It will display all of the parameters associated with the drive and its |
| 159 | partition layout. Unless the |
| 160 | .Fl r |
| 161 | flag is given, |
| 162 | the kernel's in-core copy of the label is displayed; |
| 163 | if the disk has no label, or the partition types on the disk are incorrect, |
| 164 | the kernel may have constructed or modified the label. |
| 165 | If the |
| 166 | .Fl r |
| 167 | flag is given, |
| 168 | .Nm |
| 169 | reads the label from the raw disk and displays it. Both versions are usually |
| 170 | identical except in the case where a label has not yet been initialized or |
| 171 | is corrupt. |
| 172 | .Ss Writing a standard label |
| 173 | To write a standard label, use the form |
| 174 | .Pp |
| 175 | .Nm |
| 176 | .Fl w |
| 177 | .Op Fl r |
| 178 | .Op Fl n |
| 179 | .Ar disk Ar disktype/auto |
| 180 | .Oo Ar packid Oc |
| 181 | .Pp |
| 182 | .Nm |
| 183 | .Fl w |
| 184 | .Op Fl r |
| 185 | .Op Fl n |
| 186 | .Ar disk |
| 187 | auto |
| 188 | .Pp |
| 189 | The required arguments to |
| 190 | .Nm |
| 191 | are the drive to be labeled and the drive type as described in the |
| 192 | .Xr disktab 5 |
| 193 | file. The drive parameters and partitions are taken from that file. If |
| 194 | different disks of the same physical type are to have different partitions, it |
| 195 | will be necessary to have separate disktab entries describing each, or to edit |
| 196 | the label after installation as described below. The optional argument is a |
| 197 | pack identification string, up to 16 characters long. The pack id must be |
| 198 | quoted if it contains blanks. |
| 199 | .Pp |
| 200 | If the |
| 201 | .Fl n |
| 202 | flag is given, no data will be written to the device, and instead the |
| 203 | disklabel that would have been written will be printed to stdout. |
| 204 | .Pp |
| 205 | If the |
| 206 | .Fl r |
| 207 | flag is given, the disk sectors containing the label and bootstrap |
| 208 | will be written directly. |
| 209 | A side-effect of this is that any existing bootstrap code will be overwritten |
| 210 | and the disk rendered unbootable. See the boot options below for a method of |
| 211 | writing the label and the bootstrap at the same time. |
| 212 | If |
| 213 | .Fl r |
| 214 | is not specified, |
| 215 | the existing label will be updated via the in-core copy and any bootstrap |
| 216 | code will be unaffected. |
| 217 | If the disk does not already have a label, the |
| 218 | .Fl r |
| 219 | flag must be used. |
| 220 | In either case, the kernel's in-core label is replaced. |
| 221 | .Pp |
| 222 | For a virgin disk that is not known to |
| 223 | .Xr disktab 5 , |
| 224 | .Ar disktype |
| 225 | can be specified as |
| 226 | .Dq auto . |
| 227 | In this case, the driver is requested to produce a virgin label for the |
| 228 | disk. This might or might not be successful, depending on whether the |
| 229 | driver for the disk is able to get the required data without reading |
| 230 | anything from the disk at all. It will likely succeed for all SCSI |
| 231 | disks, most IDE disks, and vnode devices. Writing a label to the |
| 232 | disk is the only supported operation, and the |
| 233 | .Ar disk |
| 234 | itself must be provided as the canonical name, i.e. not as a full |
| 235 | path name. |
| 236 | .Pp |
| 237 | For most harddisks, a label based on percentages for most partitions (and |
| 238 | one partition with a size of |
| 239 | .Ql * ) |
| 240 | will produce a reasonable configuration. |
| 241 | .Pp |
| 242 | PC-based systems have special requirements in order for the BIOS to properly |
| 243 | recognize a |
| 244 | .Dx |
| 245 | disklabel. Older systems may require what is known as a |
| 246 | .Dq dangerously dedicated |
| 247 | disklabel, which creates a fake DOS partition to work around problems older |
| 248 | BIOSes have with modern disk geometries. |
| 249 | On newer systems you generally want |
| 250 | to create a normal DOS partition using |
| 251 | .Ar fdisk |
| 252 | and then create a |
| 253 | .Dx |
| 254 | disklabel within that slice. This is described |
| 255 | later on in this page. |
| 256 | .Pp |
| 257 | Installing a new disklabel does not in of itself allow your system to boot |
| 258 | a kernel using that label. You must also install boot blocks, which is |
| 259 | described later on in this manual page. |
| 260 | .Ss Editing an existing disk label |
| 261 | To edit an existing disk label, use the form |
| 262 | .Pp |
| 263 | .Nm |
| 264 | .Fl e |
| 265 | .Op Fl r |
| 266 | .Op Fl n |
| 267 | .Ar disk |
| 268 | .Pp |
| 269 | This command reads the label from the in-core kernel copy, or directly from the |
| 270 | disk if the |
| 271 | .Fl r |
| 272 | flag is also specified. The label is written to a file in ASCII and then |
| 273 | supplied to an editor for changes. If no editor is specified in an |
| 274 | .Ev EDITOR |
| 275 | environment variable, |
| 276 | .Xr vi 1 |
| 277 | is used. When the editor terminates, the label file is used to rewrite the disk |
| 278 | label. Existing bootstrap code is unchanged regardless of whether |
| 279 | .Fl r |
| 280 | was specified. If |
| 281 | .Fl n |
| 282 | is specified, no data will be written to the device, and instead the |
| 283 | disklabel that would have been written will be printed to stdout. This is |
| 284 | useful to see how a partitioning scheme will work out for a specific disk. |
| 285 | .Ss Restoring a disk label from a file |
| 286 | To restore a disk label from a file, use the form |
| 287 | .Pp |
| 288 | .Nm |
| 289 | .Fl R |
| 290 | .Op Fl r |
| 291 | .Op Fl n |
| 292 | .Ar disk Ar protofile |
| 293 | .Pp |
| 294 | .Nm |
| 295 | is capable of restoring a disk label that was previously saved in a file in ASCII format. |
| 296 | The prototype file used to create the label should be in the same format as that |
| 297 | produced when reading or editing a label. Comments are delimited by |
| 298 | .Ar \&# |
| 299 | and newline. As when writing a new label, any existing bootstrap code will be |
| 300 | clobbered if |
| 301 | .Fl r |
| 302 | is specified and will be unaffected otherwise. See the boot options below for a |
| 303 | method of restoring the label and writing the bootstrap at the same time. |
| 304 | If |
| 305 | .Fl n |
| 306 | is used, no data will be written to the device, and instead the |
| 307 | disklabel that would have been written will be printed to stdout. This is |
| 308 | useful to see how a partitioning scheme will work out for a specific disk. |
| 309 | .Ss Enabling and disabling writing to the disk label area |
| 310 | By default, it is not possible to write to the disk label area at the beginning |
| 311 | of a disk. The disk driver arranges for |
| 312 | .Xr write 2 |
| 313 | and similar system calls |
| 314 | to return |
| 315 | .Er EROFS |
| 316 | on any attempt to do so. If you need |
| 317 | to write to this area (for example, to obliterate the label), use the form |
| 318 | .Pp |
| 319 | .Nm |
| 320 | .Fl W |
| 321 | .Ar disk |
| 322 | .Pp |
| 323 | To disallow writing to the label area after previously allowing it, use the |
| 324 | command |
| 325 | .Pp |
| 326 | .Nm |
| 327 | .Fl N |
| 328 | .Ar disk |
| 329 | .Ss Installing bootstraps |
| 330 | The final three forms of |
| 331 | .Nm |
| 332 | are used to install bootstrap code. If you are creating a |
| 333 | .Dq dangerously-dedicated |
| 334 | slice for compatibility with older PC systems, |
| 335 | you generally want to specify the raw disk name such as |
| 336 | .Pa da0 . |
| 337 | If you are creating a label within an existing DOS slice, |
| 338 | you should specify |
| 339 | the partition name such as |
| 340 | .Pa da0s1a . |
| 341 | Making a slice bootable can be tricky. If you are using a normal DOS |
| 342 | slice you typically install (or leave) a standard MBR on the base disk and |
| 343 | then install the |
| 344 | .Dx |
| 345 | bootblocks in the slice. |
| 346 | .Pp |
| 347 | .Nm |
| 348 | .Fl B |
| 349 | .Oo |
| 350 | .Fl b Ar boot1 |
| 351 | .Fl s Ar boot2 |
| 352 | .Oc |
| 353 | .Ar disk |
| 354 | .Oo Ar disktype Oc |
| 355 | .Pp |
| 356 | This form installs the bootstrap only. It does not change the disk label. |
| 357 | You should never use this command on a base disk unless you intend to create a |
| 358 | .Dq dangerously-dedicated |
| 359 | disk, such as |
| 360 | .Ar da0 . |
| 361 | This command is typically run on a slice such as |
| 362 | .Ar da0s1 . |
| 363 | .Pp |
| 364 | .Nm |
| 365 | .Fl w |
| 366 | .Fl B |
| 367 | .Op Fl n |
| 368 | .Oo |
| 369 | .Fl b Ar boot1 |
| 370 | .Fl s Ar boot2 |
| 371 | .Oc |
| 372 | .Ar disk Ar disktype |
| 373 | .Oo Ar packid Oc |
| 374 | .Pp |
| 375 | This form corresponds to the |
| 376 | .Dq write label |
| 377 | command described above. |
| 378 | In addition to writing a new volume label, it also installs the bootstrap. |
| 379 | If run on a base disk this command will create a |
| 380 | .Dq dangerously-dedicated |
| 381 | label. This command is normally run on a slice rather than a base disk. |
| 382 | If |
| 383 | .Fl n |
| 384 | is used, no data will be written to the device, and instead the |
| 385 | disklabel that would have been written will be printed to stdout. |
| 386 | .Pp |
| 387 | .Nm |
| 388 | .Fl R |
| 389 | .Fl B |
| 390 | .Op Fl n |
| 391 | .Oo |
| 392 | .Fl b Ar boot1 |
| 393 | .Fl s Ar boot2 |
| 394 | .Oc |
| 395 | .Ar disk Ar protofile |
| 396 | .Oo Ar disktype Oc |
| 397 | .Pp |
| 398 | This form corresponds to the |
| 399 | .Dq restore label |
| 400 | command described above. |
| 401 | In addition to restoring the volume label, it also installs the bootstrap. |
| 402 | If run on a base disk this command will create a |
| 403 | .Dq dangerously-dedicated |
| 404 | label. This command is normally run on a slice rather than a base disk. |
| 405 | .Pp |
| 406 | The bootstrap commands always access the disk directly, so it is not necessary |
| 407 | to specify the |
| 408 | .Fl r |
| 409 | flag. If |
| 410 | .Fl n |
| 411 | is used, no data will be written to the device, and instead the |
| 412 | disklabel that would have been written will be printed to stdout. |
| 413 | .Pp |
| 414 | The bootstrap code is comprised of two boot programs. Specify the name of the |
| 415 | boot programs to be installed in one of these ways: |
| 416 | .Bl -enum |
| 417 | .It |
| 418 | Specify the names explicitly with the |
| 419 | .Fl b |
| 420 | and |
| 421 | .Fl s |
| 422 | flags. |
| 423 | .Fl b |
| 424 | indicates the primary boot program and |
| 425 | .Fl s |
| 426 | the secondary boot program. The boot programs are located in |
| 427 | .Pa /boot . |
| 428 | .It |
| 429 | If the |
| 430 | .Fl b |
| 431 | and |
| 432 | .Fl s |
| 433 | flags are not specified, but |
| 434 | .Ar disktype |
| 435 | was specified, the names of the programs are taken from the |
| 436 | .Dq b0 |
| 437 | and |
| 438 | .Dq b1 |
| 439 | parameters of the |
| 440 | .Xr disktab 5 |
| 441 | entry for the disk if the disktab entry exists and includes those parameters. |
| 442 | .It |
| 443 | Otherwise, the default boot image names are used: |
| 444 | .Pa /boot/boot1 |
| 445 | and |
| 446 | .Pa /boot/boot2 |
| 447 | for the standard stage1 and stage2 boot images (details may vary |
| 448 | on architectures like the Alpha, where only a single-stage boot is used). |
| 449 | .El |
| 450 | .Ss Initializing/Formatting a bootable disk from scratch |
| 451 | To initialize a disk from scratch the following sequence is recommended. |
| 452 | Please note that this will wipe everything that was previously on the disk, |
| 453 | including any |
| 454 | .No non- Ns Dx |
| 455 | slices. |
| 456 | .Bl -enum |
| 457 | .It |
| 458 | Use |
| 459 | .Xr fdisk 8 |
| 460 | to initialize the hard disk, and create a slice table, referred to |
| 461 | as the |
| 462 | .Dq "partition table" |
| 463 | in |
| 464 | .Tn DOS . |
| 465 | .It |
| 466 | Use |
| 467 | .Nm |
| 468 | to define partitions on |
| 469 | .Dx |
| 470 | slices created in the previous step. |
| 471 | .It |
| 472 | Finally use |
| 473 | .Xr newfs 8 |
| 474 | to create file systems on new partitions. |
| 475 | .El |
| 476 | .Pp |
| 477 | A typical partitioning scheme would be to have an |
| 478 | .Ql a |
| 479 | partition |
| 480 | of approximately 128MB to hold the root file system, a |
| 481 | .Ql b |
| 482 | partition for |
| 483 | swap, a |
| 484 | .Ql d |
| 485 | partition for |
| 486 | .Pa /var |
| 487 | (usually 128MB), an |
| 488 | .Ql e |
| 489 | partition |
| 490 | for |
| 491 | .Pa /var/tmp |
| 492 | (usually 128MB), an |
| 493 | .Ql f |
| 494 | partition for |
| 495 | .Pa /usr |
| 496 | (usually around 2GB), |
| 497 | and finally a |
| 498 | .Ql g |
| 499 | partition for |
| 500 | .Pa /home |
| 501 | (usually all remaining space). |
| 502 | Your mileage may vary. |
| 503 | .Pp |
| 504 | .Nm fdisk Fl BI Pa da0 |
| 505 | .Pp |
| 506 | .Nm |
| 507 | .Fl w B |
| 508 | .Pa da0s1 |
| 509 | .Cm auto |
| 510 | .Pp |
| 511 | .Nm |
| 512 | .Fl e |
| 513 | .Pa da0s1 |
| 514 | .Sh FILES |
| 515 | .Bl -tag -width ".Pa /etc/disktab" -compact |
| 516 | .It Pa /boot/boot |
| 517 | Default boot image. |
| 518 | .It Pa /etc/disktab |
| 519 | Disk description file. |
| 520 | .El |
| 521 | .Sh SAVED FILE FORMAT |
| 522 | The |
| 523 | .Nm |
| 524 | utility |
| 525 | uses an |
| 526 | .Tn ASCII |
| 527 | version of the label when examining, editing, or restoring a disk |
| 528 | label. |
| 529 | The format is: |
| 530 | .Bd -literal -offset 4n |
| 531 | # /dev/da1c: |
| 532 | type: SCSI |
| 533 | disk: da0s1 |
| 534 | label: |
| 535 | flags: |
| 536 | bytes/sector: 512 |
| 537 | sectors/track: 51 |
| 538 | tracks/cylinder: 19 |
| 539 | sectors/cylinder: 969 |
| 540 | cylinders: 1211 |
| 541 | sectors/unit: 1173930 |
| 542 | rpm: 3600 |
| 543 | interleave: 1 |
| 544 | trackskew: 0 |
| 545 | cylinderskew: 0 |
| 546 | headswitch: 0 # milliseconds |
| 547 | track-to-track seek: 0 # milliseconds |
| 548 | drivedata: 0 |
| 549 | |
| 550 | 8 partitions: |
| 551 | # size offset fstype [fsize bsize bps/cpg] |
| 552 | a: 81920 0 4.2BSD 1024 8192 16 # (Cyl. 0 - 84*) |
| 553 | b: 160000 81920 swap # (Cyl. 84* - 218*) |
| 554 | c: 1173930 0 unused 0 0 # (Cyl. 0 - 1211*) |
| 555 | h: 962010 211920 vinum # (Cyl. 218*- 1211*) |
| 556 | .Ed |
| 557 | .Pp |
| 558 | Lines starting with a |
| 559 | .Ql # |
| 560 | mark are comments. |
| 561 | Most of the other specifications are no longer used. |
| 562 | The ones which must still be set correctly are: |
| 563 | .Pp |
| 564 | .Bl -inset |
| 565 | .It Ar label |
| 566 | is an optional label, set by the |
| 567 | .Ar packid |
| 568 | option when writing a label. |
| 569 | .It Ar flags |
| 570 | may be |
| 571 | .Cm removable , ecc |
| 572 | or |
| 573 | .Cm badsect . |
| 574 | .Cm removable |
| 575 | is set for removable media drives, but no current |
| 576 | .Dx |
| 577 | driver evaluates this |
| 578 | flag. |
| 579 | .Cm ecc |
| 580 | is no longer supported; |
| 581 | .Cm badsect |
| 582 | specifies that the drive can perform bad sector remapping. |
| 583 | .It Ar sectors/unit |
| 584 | describes the total size of the disk. |
| 585 | This value must be correct. |
| 586 | .It Ar "the partition table" |
| 587 | is the |
| 588 | .Ux |
| 589 | partition table, not the |
| 590 | .Tn DOS |
| 591 | partition table described in |
| 592 | .Xr fdisk 8 . |
| 593 | .El |
| 594 | .Pp |
| 595 | The partition table can have up to 8 entries. |
| 596 | It contains the following information: |
| 597 | .Bl -tag -width indent |
| 598 | .It Ar # |
| 599 | The partition identifier is a single letter in the range |
| 600 | .Ql a |
| 601 | to |
| 602 | .Ql h . |
| 603 | By convention, partition |
| 604 | .Ql c |
| 605 | is reserved to describe the entire disk. |
| 606 | .It Ar size |
| 607 | The size of the partition in sectors, |
| 608 | .Cm K |
| 609 | (kilobytes - 1024), |
| 610 | .Cm M |
| 611 | (megabytes - 1024*1024), |
| 612 | .Cm G |
| 613 | (gigabytes - 1024*1024*1024), |
| 614 | .Cm % |
| 615 | (percentage of free space |
| 616 | .Em after |
| 617 | removing any fixed-size partitions other than partition |
| 618 | .Ql c ) , |
| 619 | or |
| 620 | .Cm * |
| 621 | (all remaining free space |
| 622 | .Em after |
| 623 | fixed-size and percentage partitions). |
| 624 | For partition |
| 625 | .Ql c , |
| 626 | a size of |
| 627 | .Cm * |
| 628 | indicates the entire disk. |
| 629 | Lowercase versions of |
| 630 | .Cm K , M , |
| 631 | and |
| 632 | .Cm G |
| 633 | are allowed. |
| 634 | Size and type should be specifed without any spaces between them. |
| 635 | .Pp |
| 636 | Example: 2097152, 1G, 1024M and 1048576K are all the same size |
| 637 | (assuming 512-byte sectors). |
| 638 | .It Ar offset |
| 639 | The offset of the start of the partition from the beginning of the |
| 640 | drive in sectors, or |
| 641 | .Cm * |
| 642 | to have |
| 643 | .Nm |
| 644 | calculate the correct offset to use (the end of the previous partition plus |
| 645 | one, ignoring partition |
| 646 | .Ql c . |
| 647 | For partition |
| 648 | .Ql c , |
| 649 | .Cm * |
| 650 | will be interpreted as an offset of 0. |
| 651 | .It Ar fstype |
| 652 | Describes the purpose of the partition. |
| 653 | The example shows all currently used partition types. |
| 654 | For |
| 655 | .Tn UFS |
| 656 | file systems and |
| 657 | .Xr ccd 4 |
| 658 | partitions, use type |
| 659 | .Cm 4.2BSD . |
| 660 | For Vinum drives, use type |
| 661 | .Cm vinum . |
| 662 | Other common types are |
| 663 | .Cm swap |
| 664 | and |
| 665 | .Cm unused . |
| 666 | By convention, partition |
| 667 | .Ql c |
| 668 | represents the entire slice and should be of type |
| 669 | .Cm unused , |
| 670 | though |
| 671 | .Nm |
| 672 | does not enforce this convention. |
| 673 | The |
| 674 | .Nm |
| 675 | utility |
| 676 | also knows about a number of other partition types, |
| 677 | none of which are in current use. |
| 678 | (See the definitions starting with |
| 679 | .Dv FS_UNUSED |
| 680 | in |
| 681 | .In sys/disklabel.h |
| 682 | for more details). |
| 683 | .It Ar fsize |
| 684 | For |
| 685 | .Cm 4.2BSD |
| 686 | and |
| 687 | .Tn LFS |
| 688 | file systems only, the fragment size. |
| 689 | Defaults to 1024 for partitions smaller than 1GB, |
| 690 | 2048 for partitions 1GB or larger. |
| 691 | .It Ar bsize |
| 692 | For |
| 693 | .Cm 4.2BSD |
| 694 | and |
| 695 | .Tn LFS |
| 696 | file systems only, the block size. |
| 697 | Defaults to 8192 for partitions smaller than 1GB, |
| 698 | 16384 for partitions 1GB or larger. |
| 699 | .It Ar bps/cpg |
| 700 | For |
| 701 | .Cm 4.2BSD |
| 702 | file systems, the number of cylinders in a cylinder group. |
| 703 | For |
| 704 | .Tn LFS |
| 705 | file systems, the segment shift value. |
| 706 | Defaults to 16 for partitions smaller than 1GB, |
| 707 | 64 for partitions 1GB or larger. |
| 708 | .El |
| 709 | .Pp |
| 710 | The remainder of the line is a comment and shows the cylinder allocations based |
| 711 | on the obsolete (but possibly correct) geometry information about the drive. |
| 712 | The asterisk |
| 713 | .Pq Ql * |
| 714 | indicates that the partition does not begin or end exactly on a |
| 715 | cylinder boundary. |
| 716 | .Sh EXAMPLES |
| 717 | .Dl "disklabel da0s1" |
| 718 | .Pp |
| 719 | Display the in-core label for the first slice of the |
| 720 | .Pa da0 |
| 721 | disk, as obtained via |
| 722 | .Pa /dev/da0s1 . |
| 723 | (If the disk is |
| 724 | .Dq dangerously-dedicated , |
| 725 | the base disk name should be specified, such as |
| 726 | .Pa da0 . ) |
| 727 | .Pp |
| 728 | .Dl "disklabel da0s1 > savedlabel" |
| 729 | .Pp |
| 730 | Save the in-core label for |
| 731 | .Pa da0s1 |
| 732 | into the file |
| 733 | .Pa savedlabel . |
| 734 | This file can be used with the |
| 735 | .Fl R |
| 736 | option to restore the label at a later date. |
| 737 | .Pp |
| 738 | .Dl "disklabel -w -r /dev/da0s1 da2212 foo" |
| 739 | .Pp |
| 740 | Create a label for |
| 741 | .Pa da0s1 |
| 742 | based on information for |
| 743 | .Dq da2212 |
| 744 | found in |
| 745 | .Pa /etc/disktab . |
| 746 | Any existing bootstrap code will be clobbered |
| 747 | and the disk rendered unbootable. |
| 748 | .Pp |
| 749 | .Dl "disklabel -e -r da0s1" |
| 750 | .Pp |
| 751 | Read the on-disk label for |
| 752 | .Pa da0s1 , |
| 753 | edit it, and reinstall in-core as well as on-disk. |
| 754 | Existing bootstrap code is unaffected. |
| 755 | .Pp |
| 756 | .Dl "disklabel -e -r -n da0s1" |
| 757 | .Pp |
| 758 | Read the on-disk label for |
| 759 | .Pa da0s1 , |
| 760 | edit it, and display what the new label would be (in sectors). |
| 761 | It does |
| 762 | .Em not |
| 763 | install the new label either in-core or on-disk. |
| 764 | .Pp |
| 765 | .Dl "disklabel -r -w da0s1 auto" |
| 766 | .Pp |
| 767 | Try to auto-detect the required information from |
| 768 | .Pa da0s1 , |
| 769 | and write a new label to the disk. |
| 770 | Use another |
| 771 | .Nm Fl e |
| 772 | command to edit the |
| 773 | partitioning and file system information. |
| 774 | .Pp |
| 775 | .Dl "disklabel -R da0s1 savedlabel" |
| 776 | .Pp |
| 777 | Restore the on-disk and in-core label for |
| 778 | .Pa da0s1 |
| 779 | from information in |
| 780 | .Pa savedlabel . |
| 781 | Existing bootstrap code is unaffected. |
| 782 | .Pp |
| 783 | .Dl "disklabel -R -n da0s1 label_layout" |
| 784 | .Pp |
| 785 | Display what the label would be for |
| 786 | .Pa da0s1 |
| 787 | using the partition layout in |
| 788 | .Pa label_layout . |
| 789 | This is useful for determining how much space would be alloted for various |
| 790 | partitions with a labelling scheme using |
| 791 | .Cm % Ns -based |
| 792 | or |
| 793 | .Cm * |
| 794 | partition sizes. |
| 795 | .Pp |
| 796 | .Dl disklabel -B da0s1 |
| 797 | .Pp |
| 798 | Install a new bootstrap on |
| 799 | .Pa da0s1 . |
| 800 | The boot code comes from |
| 801 | .Pa /boot/boot1 |
| 802 | and possibly |
| 803 | .Pa /boot/boot2 . |
| 804 | On-disk and in-core labels are unchanged. |
| 805 | .Pp |
| 806 | .Dl disklabel -w -B /dev/da0s1 -b newboot1 -s newboot2 da2212 |
| 807 | .Pp |
| 808 | Install a new label and bootstrap. |
| 809 | The label is derived from disktab information for |
| 810 | .Dq da2212 |
| 811 | and installed both in-core and on-disk. |
| 812 | The bootstrap code comes from the files |
| 813 | .Pa /boot/newboot1 |
| 814 | and |
| 815 | .Pa /boot/newboot2 . |
| 816 | .Pp |
| 817 | .Dl dd if=/dev/zero of=/dev/da0 bs=512 count=32 |
| 818 | .Dl fdisk -BI da0 |
| 819 | .Dl dd if=/dev/zero of=/dev/da0s1 bs=512 count=32 |
| 820 | .Dl disklabel -w -B da0s1 auto |
| 821 | .Dl disklabel -e da0s1 |
| 822 | .Pp |
| 823 | Completely wipe any prior information on the disk, creating a new bootable |
| 824 | disk with a DOS partition table containing one |
| 825 | .Dq whole-disk |
| 826 | slice. Then |
| 827 | initialize the slice, then edit it to your needs. The |
| 828 | .Pa dd |
| 829 | commands are optional, but may be necessary for some BIOSes to properly |
| 830 | recognize the disk. |
| 831 | .Pp |
| 832 | This is an example disklabel that uses some of the new partition size types |
| 833 | such as |
| 834 | .Cm % , M , G , |
| 835 | and |
| 836 | .Cm * , |
| 837 | which could be used as a source file for |
| 838 | .Pp |
| 839 | .Dl disklabel -R ad0s1c new_label_file |
| 840 | .Bd -literal -offset 4n |
| 841 | # /dev/ad0s1c: |
| 842 | type: ESDI |
| 843 | disk: ad0s1 |
| 844 | label: |
| 845 | flags: |
| 846 | bytes/sector: 512 |
| 847 | sectors/track: 63 |
| 848 | tracks/cylinder: 16 |
| 849 | sectors/cylinder: 1008 |
| 850 | cylinders: 40633 |
| 851 | sectors/unit: 40959009 |
| 852 | rpm: 3600 |
| 853 | interleave: 1 |
| 854 | trackskew: 0 |
| 855 | cylinderskew: 0 |
| 856 | headswitch: 0 # milliseconds |
| 857 | track-to-track seek: 0 # milliseconds |
| 858 | drivedata: 0 |
| 859 | |
| 860 | 8 partitions: |
| 861 | # size offset fstype [fsize bsize bps/cpg] |
| 862 | a: 400M 0 4.2BSD 4096 16384 75 # (Cyl. 0 - 812*) |
| 863 | b: 1G * swap |
| 864 | c: * * unused |
| 865 | e: 204800 * 4.2BSD |
| 866 | f: 5g * 4.2BSD |
| 867 | g: * * 4.2BSD |
| 868 | .Ed |
| 869 | .Sh DIAGNOSTICS |
| 870 | The kernel device drivers will not allow the size of a disk partition |
| 871 | to be decreased or the offset of a partition to be changed while it is open. |
| 872 | Some device drivers create a label containing only a single large partition |
| 873 | if a disk is unlabeled; thus, the label must be written to the |
| 874 | .Dq a |
| 875 | partition of the disk while it is open. This sometimes requires the desired |
| 876 | label to be set in two steps, the first one creating at least one other |
| 877 | partition, and the second setting the label on the new partition while shrinking |
| 878 | the |
| 879 | .Dq a |
| 880 | partition. |
| 881 | .Pp |
| 882 | On some machines the bootstrap code may not fit entirely in the area |
| 883 | allocated for it by some file systems. |
| 884 | As a result, it may not be possible to have file systems on some partitions |
| 885 | of a |
| 886 | .Dq bootable |
| 887 | disk. |
| 888 | When installing bootstrap code, |
| 889 | .Nm |
| 890 | checks for these cases. |
| 891 | If the installed boot code would overlap a partition of type FS_UNUSED |
| 892 | it is marked as type FS_BOOT. |
| 893 | The |
| 894 | .Xr newfs 8 |
| 895 | utility will disallow creation of file systems on FS_BOOT partitions. |
| 896 | Conversely, if a partition has a type other than FS_UNUSED or FS_BOOT, |
| 897 | .Nm |
| 898 | will not install bootstrap code that overlaps it. |
| 899 | .Sh SEE ALSO |
| 900 | .Xr ccd 4 , |
| 901 | .Xr disklabel 5 , |
| 902 | .Xr disktab 5 , |
| 903 | .Xr boot0cfg 8 , |
| 904 | .Xr fdisk 8 , |
| 905 | .Xr vinum 8 |
| 906 | .Sh BUGS |
| 907 | When a disk name is given without a full pathname, |
| 908 | the constructed device name uses the |
| 909 | .Dq c |
| 910 | partition. |
| 911 | .Pp |
| 912 | For the i386 architecture, the primary bootstrap sector contains |
| 913 | an embedded |
| 914 | .Em fdisk |
| 915 | table. |
| 916 | The |
| 917 | .Nm |
| 918 | utility takes care to not clobber it when installing a bootstrap only |
| 919 | .Pq Fl B , |
| 920 | or when editing an existing label |
| 921 | .Pq Fl e , |
| 922 | but it unconditionally writes the primary bootstrap program onto |
| 923 | the disk for |
| 924 | .Fl w |
| 925 | or |
| 926 | .Fl R , |
| 927 | thus replacing the |
| 928 | .Em fdisk |
| 929 | table by the dummy one in the bootstrap program. This is only of |
| 930 | concern if the disk is fully dedicated, so that the |
| 931 | .Bx |
| 932 | disklabel |
| 933 | starts at absolute block 0 on the disk. |
| 934 | .Pp |
| 935 | The |
| 936 | .Nm |
| 937 | utility |
| 938 | does not perform all possible error checking. Warning *is* given if partitions |
| 939 | overlap; if an absolute offset does not match the expected offset; if the |
| 940 | .Dq c |
| 941 | partition does not start at 0 or does not cover the entire slice; if a |
| 942 | partition runs past the end of the device; and a number of other errors; but |
| 943 | no warning is given if space remains unused. |