1SGDISK(8) GPT fdisk Manual SGDISK(8)
2
3
4
6 sgdisk - Command-line GUID partition table (GPT) manipulator for Linux
7 and Unix
8
10 sgdisk [ options ] device
11
12
14 GPT fdisk is a text-mode menu-driven package for creation and manipula‐
15 tion of partition tables. It consists of two programs: the text-mode
16 interactive gdisk and the command-line sgdisk. Either program will au‐
17 tomatically convert an old-style Master Boot Record (MBR) partition ta‐
18 ble or BSD disklabel stored without an MBR carrier partition to the
19 newer Globally Unique Identifier (GUID) Partition Table (GPT) format,
20 or will load a GUID partition table. This man page documents the com‐
21 mand-line sgdisk program.
22
23 Some advanced data manipulation and recovery options require you to un‐
24 derstand the distinctions between the main and backup data, as well as
25 between the GPT headers and the partition tables. For information on
26 MBR vs. GPT, as well as GPT terminology and structure, see the extended
27 gdisk documentation at http://www.rodsbooks.com/gdisk/ or consult
28 Wikipedia.
29
30 The sgdisk program employs a user interface that's based entirely on
31 the command line, making it suitable for use in scripts or by experts
32 who want to make one or two quick changes to a disk. (The program may
33 query the user when certain errors are encountered, though.) The pro‐
34 gram's name is based on sfdisk, but the user options of the two pro‐
35 grams are entirely different from one another.
36
37 Ordinarily, sgdisk operates on disk device files, such as /dev/sda or
38 /dev/hda under Linux, /dev/disk0 under Mac OS X, or /dev/ad0 or
39 /dev/da0 under FreeBSD. The program can also operate on disk image
40 files, which can be either copies of whole disks (made with dd, for in‐
41 stance) or raw disk images used by emulators such as QEMU or VMWare.
42 Note that only raw disk images are supported; sgdisk cannot work on
43 compressed or other advanced disk image formats.
44
45 The MBR partitioning system uses a combination of cylinder/head/sector
46 (CHS) addressing and logical block addressing (LBA). The former is
47 klunky and limiting. GPT drops CHS addressing and uses 64-bit LBA mode
48 exclusively. Thus, GPT data structures, and therefore sgdisk, do not
49 need to deal with CHS geometries and all the problems they create.
50
51 For best results, you should use an OS-specific partition table program
52 whenever possible. For example, you should make Mac OS X partitions
53 with the Mac OS X Disk Utility program and Linux partitions with the
54 Linux gdisk, sgdisk, or GNU Parted programs.
55
56 Upon start, sgdisk attempts to identify the partition type in use on
57 the disk. If it finds valid GPT data, sgdisk will use it. If sgdisk
58 finds a valid MBR or BSD disklabel but no GPT data, it will attempt to
59 convert the MBR or disklabel into GPT form. (BSD disklabels are likely
60 to have unusable first and/or final partitions because they overlap
61 with the GPT data structures, though.) GPT fdisk can identify, but not
62 use data in, Apple Partition Map (APM) disks, which are used on 680x0-
63 and PowerPC-based Macintoshes. If you specify any option that results
64 in changes to an MBR or BSD disklabel, sgdisk ignores those changes un‐
65 less the -g (--mbrtogpt), -z (--zap), or -Z (--zap-all) option is used.
66 If you use the -g option, sgdisk replaces the MBR or disklabel with a
67 GPT. This action is potentially dangerous! Your system may become un‐
68 bootable, and partition type codes may become corrupted if the disk
69 uses unrecognized type codes. Boot problems are particularly likely if
70 you're multi-booting with any GPT-unaware OS.
71
72 The MBR-to-GPT conversion will leave at least one gap in the partition
73 numbering if the original MBR used logical partitions. These gaps are
74 harmless, but you can eliminate them by using the -s (--sort) option,
75 if you like. (Doing this may require you to update your /etc/fstab
76 file.)
77
78 When creating a fresh partition table, certain considerations may be in
79 order:
80
81
82 * For data (non-boot) disks, and for boot disks used on BIOS-based
83 computers with GRUB as the boot loader, partitions may be cre‐
84 ated in whatever order and in whatever sizes are desired.
85
86
87 * Boot disks for EFI-based systems require an EFI System Partition
88 (gdisk internal code 0xEF00) formatted as FAT-32. I recommended
89 making this partition 550 MiB. (Smaller ESPs are common, but
90 some EFIs have flaky FAT drivers that necessitate a larger par‐
91 tition for reliable operation.) Boot-related files are stored
92 here. (Note that GNU Parted identifies such partitions as having
93 the "boot flag" set.)
94
95
96 * Some boot loaders for BIOS-based systems make use of a BIOS Boot
97 Partition (gdisk internal code 0xEF02), in which the secondary
98 boot loader is stored, possibly without the benefit of a
99 filesystem. (GRUB2 may optionally use such a partition.) This
100 partition can typically be quite small (roughly 32 to 200 KiB,
101 although 1 MiB is more common in practice), but you should con‐
102 sult your boot loader documentation for details.
103
104
105 * If Windows is to boot from a GPT disk, a partition of type Mi‐
106 crosoft Reserved (sgdisk internal code 0x0C01) is recommended.
107 This partition should be about 128 MiB in size. It ordinarily
108 follows the EFI System Partition and immediately precedes the
109 Windows data partitions. (Note that GNU Parted creates all FAT
110 partitions as this type, which actually makes the partition un‐
111 usable for normal file storage in both Windows and Mac OS X.)
112
113
114 * Some OSes' GPT utilities create some blank space (typically 128
115 MiB) after each partition. The intent is to enable future disk
116 utilities to use this space. Such free space is not required of
117 GPT disks, but creating it may help in future disk maintenance.
118
119
121 Some options take no arguments, others take one argument (typically a
122 partition number), and others take compound arguments with colon delim‐
123 itation. For instance, -n (--new) takes a partition number, a starting
124 sector number, and an ending sector number, as in sgdisk -n
125 2:2000:50000 /dev/sdc, which creates a new partition, numbered 2,
126 starting at sector 2000 an ending at sector 50,000, on /dev/sdc.
127
128 Unrelated options may be combined; however, some such combinations will
129 be nonsense (such as deleting a partition and then changing its GUID
130 type code). sgdisk interprets options in the order in which they're
131 entered, so effects can vary depending on order. For instance, sgdisk
132 -s -d 2 sorts the partition table entries and then deletes partition 2
133 from the newly-sorted list; but sgdisk -d 2 -s deletes the original
134 partition 2 and then sorts the modified partition table.
135
136 Error checking and opportunities to correct mistakes in sgdisk are min‐
137 imal. Although the program endeavors to keep the GPT data structures
138 legal, it does not prompt for verification before performing its ac‐
139 tions. Unless you require a command-line-driven program, you should use
140 the interactive gdisk instead of sgdisk, since gdisk allows you to quit
141 without saving your changes, should you make a mistake.
142
143 Although sgdisk is based on the same partition-manipulation code as
144 gdisk, sgdisk implements fewer features than its interactive sibling.
145 Options available in sgdisk are:
146
147
148 -a, --set-alignment=value
149 Set the sector alignment multiple. GPT fdisk aligns the start of
150 partitions to sectors that are multiples of this value, which
151 defaults to 1 MiB (2048 on disks with 512-byte sectors) on
152 freshly formatted disks. This alignment value is necessary to
153 obtain optimum performance with Western Digital Advanced Format
154 and similar drives with larger physical than logical sector
155 sizes, with some types of RAID arrays, and with SSD devices.
156 When the -I option is used, this same alignment value is used to
157 determine partition end points; but partitions end at one less
158 than a multiple of this value, to keep the partition length a
159 multiple of this value.
160
161
162 -A, --attributes=list|[partnum:show|or|nand|xor|=|set|clear|tog‐
163 gle|get[:bitnum|hexbitmask]]
164 View or set partition attributes. Use list to see defined
165 (known) attribute values. Omit the partition number (and even
166 the device filename) when using this option. The others require
167 a partition number. The show and get options show the current
168 attribute settings (all attributes or for a particular bit, re‐
169 spectively). The or, nand, xor, =, set, clear, and toggle op‐
170 tions enable you to change the attribute bit value. The set,
171 clear, toggle, and get options work on a bit number; the others
172 work on a hexadecimal bit mask. For example, type sgdisk -A
173 4:set:2 /dev/sdc to set the bit 2 attribute (legacy BIOS
174 bootable) on partition 4 on /dev/sdc.
175
176
177 -b, --backup=file
178 Save partition data to a backup file. You can back up your cur‐
179 rent in-memory partition table to a disk file using this option.
180 The resulting file is a binary file consisting of the protective
181 MBR, the main GPT header, the backup GPT header, and one copy of
182 the partition table, in that order. Note that the backup is of
183 the current in-memory data structures, so if you launch the pro‐
184 gram, make changes, and then use this option, the backup will
185 reflect your changes. If the GPT data structures are damaged,
186 the backup may not accurately reflect the damaged state; in‐
187 stead, they will reflect GPT fdisk's first-pass interpretation
188 of the GPT.
189
190
191 -B, --byte-swap-name=partnum
192 Swap the byte order for the name of the specified partition.
193 Some partitioning tools, including GPT fdisk 1.0.7 and earlier,
194 can write the partition name in the wrong byte order on big-en‐
195 dian computers, such as the IBM s390 mainframes and PowerPC-
196 based Macs. This feature corrects this problem.
197
198
199 -c, --change-name=partnum:name
200 Change the GPT name of a partition. This name is encoded as a
201 UTF-16 string, but proper entry and display of anything beyond
202 basic ASCII values requires suitable locale and font support.
203 For the most part, Linux ignores the partition name, but it may
204 be important in some OSes. If you want to set a name that in‐
205 cludes a space, enclose it in quotation marks, as in sgdisk -c
206 1:"Sample Name" /dev/sdb. Note that the GPT name of a partition
207 is distinct from the filesystem name, which is encoded in the
208 filesystem's data structures.
209
210
211 -C, --recompute-chs
212 Recompute CHS values in protective or hybrid MBR. This option
213 can sometimes help if a disk utility, OS, or BIOS doesn't like
214 the CHS values used by the partitions in the protective or hy‐
215 brid MBR. In particular, the GPT specification requires a CHS
216 value of 0xFFFFFF for over-8GiB partitions, but this value is
217 technically illegal by the usual standards. Some BIOSes hang if
218 they encounter this value. This option will recompute a more
219 normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling
220 these BIOSes to boot.
221
222
223 -d, --delete=partnum
224 Delete a partition. This action deletes the entry from the par‐
225 tition table but does not disturb the data within the sectors
226 originally allocated to the partition on the disk. If a corre‐
227 sponding hybrid MBR partition exists, gdisk deletes it, as well,
228 and expands any adjacent 0xEE (EFI GPT) MBR protective partition
229 to fill the new free space.
230
231
232 -D, --display-alignment
233 Display current sector alignment value. Partitions will be cre‐
234 ated on multiples of the sector value reported by this option.
235 You can change the alignment value with the -a option.
236
237
238 -e, --move-second-header
239 Move backup GPT data structures to the end of the disk. Use this
240 option if you've added disks to a RAID array, thus creating a
241 virtual disk with space that follows the backup GPT data struc‐
242 tures. This command moves the backup GPT data structures to the
243 end of the disk, where they belong.
244
245
246 -E, --end-of-largest
247 Displays the sector number of the end of the largest available
248 block of sectors on the disk. A script may store this value and
249 pass it back as part of -n's option to create a partition. If no
250 unallocated sectors are available, this function returns the
251 value 0.
252
253
254 -f, --first-in-largest
255 Displays the sector number of the start of the largest available
256 block of sectors on the disk. A script may store this value and
257 pass it back as part of -n's option to create a partition. If no
258 unallocated sectors are available, this function returns the
259 value 0. Note that this parameter is blind to partition align‐
260 ment; when you actually create a partition, its start point
261 might be changed from this value.
262
263
264 -F, --first-aligned-in-largest
265 Similar to -f (--first-in-largest), except returns the sector
266 number with the current alignment correction applied. Use this
267 function if you need to compute the actual partition start point
268 rather than a theoretical start point or the actual start point
269 if you set the alignment value to 1.
270
271
272 -g, --mbrtogpt
273 Convert an MBR or BSD disklabel disk to a GPT disk. As a safety
274 measure, use of this option is required on MBR or BSD disklabel
275 disks if you intend to save your changes, in order to prevent
276 accidentally damaging such disks.
277
278
279 -G, --randomize-guids
280 Randomize the disk's GUID and all partitions' unique GUIDs (but
281 not their partition type code GUIDs). This function may be used
282 after cloning a disk in order to render all GUIDs once again
283 unique.
284
285
286 -h, --hybrid
287 Create a hybrid MBR. This option takes from one to three parti‐
288 tion numbers, separated by colons, as arguments. You may option‐
289 ally specify a final partition "EE" to indicate that the EFI GPT
290 (type 0xEE) should be placed last in the table, otherwise it
291 will be placed first, followed by the partition(s) you specify.
292 Their type codes are based on the GPT fdisk type codes divided
293 by 0x0100, which is usually correct for Windows partitions. If
294 the active/bootable flag should be set, you must do so in an‐
295 other program, such as fdisk. The gdisk program offers addi‐
296 tional hybrid MBR creation options.
297
298
299 -i, --info=partnum
300 Show detailed partition information. The summary information
301 produced by the -p command necessarily omits many details, such
302 as the partition's unique GUID and the translation of sgdisk's
303 internal partition type code to a plain type name. The -i option
304 displays this information for a single partition.
305
306
307 -I, --align-end
308 When possible, align the end points of partitions to one less
309 than a multiple of the alignment value. When both start and end
310 points are aligned, partitions should be multiples of the align‐
311 ment value in size, which is necessary for some partition en‐
312 cryption tools to function correctly. This option applies to all
313 partitions created after this option on the command line. Note
314 that this alignment is not always possible; for instance, if the
315 free space at the end of a disk is less than the alignment
316 value, with the current final partition being aligned, and if
317 sgdisk is asked to create a partition in that space, then it
318 will not be end-aligned.
319
320
321 -j, --adjust-main-table=sector
322 Adjust the location of the main partition table. This value is
323 normally 2, but it may need to be increased in some cases, such
324 as when a system-on-chip (SoC) is hard-coded to read boot code
325 from sector 2. I recommend against adjusting this value unless
326 doing so is absolutely necessary.
327
328
329 -l, --load-backup=file
330 Load partition data from a backup file. This option is the re‐
331 verse of the -b option. Note that restoring partition data from
332 anything but the original disk is not recommended. This option
333 will work even if the disk's original partition table is bad;
334 however, most other options on the same command line will be ig‐
335 nored.
336
337
338 -L, --list-types
339 Display a summary of partition types. GPT uses a GUID to iden‐
340 tify partition types for particular OSes and purposes. For ease
341 of data entry, sgdisk compresses these into two-byte (four-digit
342 hexadecimal) values that are related to their equivalent MBR
343 codes. Specifically, the MBR code is multiplied by hexadecimal
344 0x0100. For instance, the code for Linux swap space in MBR is
345 0x82, and it's 0x8200 in gdisk. A one-to-one correspondence is
346 impossible, though. Most notably, the codes for all varieties of
347 FAT and NTFS partition correspond to a single GPT code (entered
348 as 0x0700 in sgdisk). Some OSes use a single MBR code but employ
349 many more codes in GPT. For these, sgdisk adds code numbers se‐
350 quentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for
351 FreeBSD boot, 0xa502 for FreeBSD swap, and so on. Note that
352 these two-byte codes are unique to gdisk and sgdisk. This option
353 does not require you to specify a valid disk device filename.
354
355
356 -m, --gpttombr
357 Convert disk from GPT to MBR form. This option takes from one to
358 four partition numbers, separated by colons, as arguments. Their
359 type codes are based on the GPT fdisk type codes divided by
360 0x0100. If the active/bootable flag should be set, you must do
361 so in another program, such as fdisk. The gdisk program offers
362 additional MBR conversion options. It is not possible to convert
363 more than four partitions from GPT to MBR form or to convert
364 partitions that start above the 2TiB mark or that are larger
365 than 2TiB.
366
367
368 -n, --new=partnum:start:end
369 Create a new partition. You enter a partition number, starting
370 sector, and an ending sector. Both start and end sectors can be
371 specified in absolute terms as sector numbers or as positions
372 measured in kibibytes (K), mebibytes (M), gibibytes (G),
373 tebibytes (T), or pebibytes (P); for instance, 40M specifies a
374 position 40MiB from the start of the disk. You can specify loca‐
375 tions relative to the start or end of the specified default
376 range by preceding the number by a '+' or '-' symbol, as in +2G
377 to specify a point 2GiB after the default start sector, or -200M
378 to specify a point 200MiB before the last available sector. A
379 start or end value of 0 specifies the default value, which is
380 the start of the largest available block for the start sector
381 and the end of the same block for the end sector. A partnum
382 value of 0 causes the program to use the first available parti‐
383 tion number. Subsequent uses of the -A (--attributes), -c
384 (--change-name), -t (--typecode), and -u (--partition-guid) op‐
385 tions may also use 0 to refer to the same partition.
386
387
388 -N, --largest-new=num
389 Create a new partition that fills the largest available block of
390 space on the disk. You can use the -a (--set-alignment) option
391 to adjust the alignment, if desired. A num value of 0 causes the
392 program to use the first available partition number.
393
394
395 -o, --clear
396 Clear out all partition data. This includes GPT header data, all
397 partition definitions, and the protective MBR. Note that this
398 operation will, like most other operations, fail on a damaged
399 disk. If you want to prepare a disk you know to be damaged for
400 GPT use, you should first wipe it with -Z and then partition it
401 normally. This option will work even if the disk's original par‐
402 tition table is bad; however, most other options on the same
403 command line will be ignored.
404
405
406 -O, --print-mbr
407 Display basic MBR partition summary data. This includes parti‐
408 tion numbers, starting and ending sector numbers, partition
409 sizes, MBR partition types codes, and partition names. This op‐
410 tion is useful mainly for diagnosing partition table problems,
411 particularly on disks with hybrid MBRs.
412
413
414 -p, --print
415 Display basic GPT partition summary data. This includes parti‐
416 tion numbers, starting and ending sector numbers, partition
417 sizes, sgdisk's partition types codes, and partition names. For
418 additional information, use the -i (--info) option.
419
420
421 -P, --pretend
422 Pretend to make specified changes. In-memory GPT data structures
423 are altered according to other parameters, but changes are not
424 written to disk.
425
426
427 -r, --transpose
428 Swap two partitions' entries in the partition table. One or both
429 partitions may be empty, although swapping two empty partitions
430 is pointless. For instance, if partitions 1-4 are defined,
431 transposing 1 and 5 results in a table with partitions numbered
432 from 2-5. Transposing partitions in this way has no effect on
433 their disk space allocation; it only alters their order in the
434 partition table.
435
436
437 -R, --replicate=second_device_filename
438 Replicate the main device's partition table on the specified
439 second device. Note that the replicated partition table is an
440 exact copy, including all GUIDs; if the device should have its
441 own unique GUIDs, you should use the -G option on the new disk.
442
443
444 -s, --sort
445 Sort partition entries. GPT partition numbers need not match the
446 order of partitions on the disk. If you want them to match, you
447 can use this option. Note that some partitioning utilities sort
448 partitions whenever they make changes. Such changes will be re‐
449 flected in your device filenames, so you may need to edit
450 /etc/fstab if you use this option.
451
452
453 -t, --typecode=partnum:{hexcode|GUID}
454 Change a single partition's type code. You enter the type code
455 using either a two-byte hexadecimal number, as described ear‐
456 lier, or a fully-specified GUID value, such as
457 EBD0A0A2-B9E5-4433-87C0-68B6B72699C7.
458
459
460 -T, --transform-bsd=partnum
461 Transform BSD partitions into GPT partitions. This option works
462 on BSD disklabels held within GPT (or converted MBR) partitions.
463 Converted partitions' type codes are likely to need manual ad‐
464 justment. sgdisk will attempt to convert BSD disklabels stored
465 on the main disk when launched, but this conversion is likely to
466 produce first and/or last partitions that are unusable. The many
467 BSD variants means that the probability of sgdisk being unable
468 to convert a BSD disklabel is high compared to the likelihood of
469 problems with an MBR conversion.
470
471
472 -u, --partition-guid=partnum:guid
473 Set the partition unique GUID for an individual partition. The
474 GUID may be a complete GUID or 'R' to set a random GUID.
475
476
477 -U, --disk-guid=guid
478 Set the GUID for the disk. The GUID may be a complete GUID or
479 'R' to set a random GUID.
480
481
482 --usage
483 Print a brief summary of available options.
484
485
486 -v, --verify
487 Verify disk. This option checks for a variety of problems, such
488 as incorrect CRCs and mismatched main and backup data. This op‐
489 tion does not automatically correct most problems, though; for
490 that, you must use options on the recovery & transformation
491 menu. If no problems are found, this command displays a summary
492 of unallocated disk space. This option will work even if the
493 disk's original partition table is bad; however, most other op‐
494 tions on the same command line will be ignored.
495
496
497 -V, --version
498 Display program version information. This option may be used
499 without specifying a device filename.
500
501
502 -z, --zap
503 Zap (destroy) the GPT data structures and then exit. Use this
504 option if you want to repartition a GPT disk using fdisk or some
505 other GPT-unaware program. This option destroys only the GPT
506 data structures; it leaves the MBR intact. This makes it useful
507 for wiping out GPT data structures after a disk has been repar‐
508 titioned for MBR using a GPT-unaware utility; however, there's a
509 risk that it will damage boot loaders or even the start of the
510 first or end of the last MBR partition. If you use it on a valid
511 GPT disk, the MBR will be left with an inappropriate EFI GPT
512 (0xEE) partition definition, which you can delete using another
513 utility.
514
515
516 -Z, --zap-all
517 Zap (destroy) the GPT and MBR data structures and then exit.
518 This option works much like -z, but as it wipes the MBR as well
519 as the GPT, it's more suitable if you want to repartition a disk
520 after using this option, and completely unsuitable if you've al‐
521 ready repartitioned the disk.
522
523
524 -?, --help
525 Print a summary of options.
526
527
529 sgdisk returns various values depending on its success or failure:
530
531
532 0 Normal program execution
533
534
535 1 Too few arguments
536
537
538 2 An error occurred while reading the partition table
539
540
541 3 Non-GPT disk detected and no -g option, but operation requires a
542 write action
543
544
545 4 An error prevented saving changes
546
547
548 5 An error occurred while reading standard input (should never oc‐
549 cur with sgdisk, but may with gdisk)
550
551
552 8 Disk replication operation (-R) failed
553
554
556 Known bugs and limitations include:
557
558
559 * The program compiles correctly only on Linux, FreeBSD, and Mac
560 OS X. Linux versions for x86-64 (64-bit), x86 (32-bit), and Pow‐
561 erPC (32-bit) have been tested, with the x86-64 version having
562 seen the most testing.
563
564
565 * The FreeBSD version of the program can't write changes to the
566 partition table to a disk when existing partitions on that disk
567 are mounted. (The same problem exists with many other FreeBSD
568 utilities, such as gpt, fdisk, and dd.) This limitation can be
569 overcome by typing sysctl kern.geom.debugflags=16 at a shell
570 prompt.
571
572
573 * The fields used to display the start and end sector numbers for
574 partitions in the -p option are 14 characters wide. This trans‐
575 lates to a limitation of about 45 PiB. On larger disks, the dis‐
576 played columns will go out of alignment.
577
578
579 * The program can load only up to 128 partitions (4 primary parti‐
580 tions and 124 logical partitions) when converting from MBR for‐
581 mat. This limit can be raised by changing the #define
582 MAX_MBR_PARTS line in the basicmbr.h source code file and recom‐
583 piling; however, such a change will require using a
584 larger-than-normal partition table. (The limit of 128 partitions
585 was chosen because that number equals the 128 partitions sup‐
586 ported by the most common partition table size.)
587
588
589 * Converting from MBR format sometimes fails because of insuffi‐
590 cient space at the start or (more commonly) the end of the disk.
591 Resizing the partition table (using the 's' option in the ex‐
592 perts' menu) can sometimes overcome this problem; however, in
593 extreme cases it may be necessary to resize a partition using
594 GNU Parted or a similar tool prior to conversion with gdisk.
595
596
597 * MBR conversions work only if the disk has correct LBA partition
598 descriptors. These descriptors should be present on any disk
599 over 8 GiB in size or on smaller disks partitioned with any but
600 very ancient software.
601
602
603 * BSD disklabel support can create first and/or last partitions
604 that overlap with the GPT data structures. This can sometimes be
605 compensated by adjusting the partition table size, but in ex‐
606 treme cases the affected partition(s) may need to be deleted.
607
608
609 * Because of the highly variable nature of BSD disklabel struc‐
610 tures, conversions from this form may be unreliable -- parti‐
611 tions may be dropped, converted in a way that creates overlaps
612 with other partitions, or converted with incorrect start or end
613 values. Use this feature with caution!
614
615
616 * Booting after converting an MBR or BSD disklabel disk is likely
617 to be disrupted. Sometimes re-installing a boot loader will fix
618 the problem, but other times you may need to switch boot load‐
619 ers. Except on EFI-based platforms, Windows through at least
620 Windows 7 RC doesn't support booting from GPT disks. Creating a
621 hybrid MBR (using the 'h' option on the recovery & transforma‐
622 tion menu) or abandoning GPT in favor of MBR may be your only
623 options in this case.
624
625
627 Primary author: Roderick W. Smith (rodsmith@rodsbooks.com)
628
629 Contributors:
630
631 * Yves Blusseau (1otnwmz02@sneakemail.com)
632
633 * David Hubbard (david.c.hubbard@gmail.com)
634
635 * Justin Maggard (justin.maggard@netgear.com)
636
637 * Dwight Schauer (das@teegra.net)
638
639 * Florian Zumbiehl (florz@florz.de)
640
641
642
644 cfdisk(8), cgdisk(8), fdisk(8), gdisk(8), mkfs(8), parted(8),
645 sfdisk(8), fixparts(8).
646
647 http://en.wikipedia.org/wiki/GUID_Partition_Table
648
649 http://developer.apple.com/technotes/tn2006/tn2166.html
650
651 http://www.rodsbooks.com/gdisk/
652
653
655 The sgdisk command is part of the GPT fdisk package and is available
656 from Rod Smith.
657
658
659
660Roderick W. Smith 1.0.9 SGDISK(8)