# sgdisk(8) - man - phpman

> **TLDR:** Manage GUID Partition Tables (GPT).
>
- Display basic GPT partition summary data for a device:
  `sudo sgdisk {{-p|--print}} {{/dev/sdX}}`
- Wipe both GPT and MBR data structures from a device (destroys all partition information):
  `sudo sgdisk {{-Z|--zap-all}} {{/dev/sdX}}`
- Convert a GPT disk to MBR format using up to four partitions:
  `sudo sgdisk {{-m|--gpttombr}} {{1:2:3:4}} {{/dev/sdX}}`
- Delete a partition entry by number (data in sectors remains untouched):
  `sudo sgdisk {{-d|--delete}} {{1}} {{/dev/sdX}}`
- Save the current in-memory GPT data (protective MBR, headers, and table) to a binary backup file:
  `sudo sgdisk {{-b|--backup}} {{/path/to/backup.gpt}} {{/dev/sdX}}`
- Load GPT data from a backup file (restoring from a non-original disk is not recommended):
  `sudo sgdisk {{-l|--load-backup}} {{/path/to/backup.gpt}} {{/dev/sdX}}`
- Verify GPT structures for CRC errors, mismatches, or inconsistencies:
  `sudo sgdisk {{-v|--verify}} {{/dev/sdX}}`
- Display a summary of available partition type codes (no device required):
  `sgdisk {{-L|--list-types}}`

*Source: tldr-pages*

---

[SGDISK(8)](https://www.chedong.com/phpMan.php/man/SGDISK/8/markdown)                                 GPT fdisk Manual                                 [SGDISK(8)](https://www.chedong.com/phpMan.php/man/SGDISK/8/markdown)



## NAME
       sgdisk - Command-line GUID partition table (GPT) manipulator for Linux and Unix

## SYNOPSIS
       **sgdisk** [ options ] _device_


## DESCRIPTION
       GPT  fdisk  is a text-mode menu-driven package for creation and manipulation of partition ta‐
       bles. It consists of two programs: the  text-mode  interactive  **gdisk**  and  the  command-line
       **sgdisk**.  Either program will automatically convert an old-style Master Boot Record (MBR) par‐
       tition table or BSD disklabel stored without an MBR carrier partition to the  newer  Globally
       Unique  Identifier  (GUID) Partition Table (GPT) format, or will load a GUID partition table.
       This man page documents the command-line **sgdisk** program.

       Some advanced data manipulation and recovery options require you to understand  the  distinc‐
       tions  between the main and backup data, as well as between the GPT headers and the partition
       tables. For information on MBR vs. GPT, as well as GPT terminology and structure, see the ex‐
       tended **gdisk** documentation at _<http://www.rodsbooks.com/gdisk/_> or consult Wikipedia.

       The **sgdisk** program employs a user interface that's based entirely on the command line, making
       it suitable for use in scripts or by experts who want to make one or two quick changes  to  a
       disk.  (The program may query the user when certain errors are encountered, though.) The pro‐
       gram's name is based on **sfdisk**, but the user options of the two programs are entirely differ‐
       ent from one another.

       Ordinarily,  **sgdisk**  operates on disk device files, such as _/dev/sda_ or _/dev/hda_ under Linux,
       _/dev/disk0_ under Mac OS X, or _/dev/ad0_ or _/dev/da0_ under FreeBSD. The program can also  oper‐
       ate  on  disk  image  files, which can be either copies of whole disks (made with **dd**, for in‐
       stance) or raw disk images used by emulators such as QEMU or VMWare. Note that only _raw_  disk
       images are supported; **sgdisk** cannot work on compressed or other advanced disk image formats.

       The  MBR  partitioning system uses a combination of cylinder/head/sector (CHS) addressing and
       logical block addressing (LBA). The former is klunky and limiting. GPT drops  CHS  addressing
       and uses 64-bit LBA mode exclusively. Thus, GPT data structures, and therefore **sgdisk**, do not
       need to deal with CHS geometries and all the problems they create.

       For best results, you should use an OS-specific partition table  program  whenever  possible.
       For  example,  you should make Mac OS X partitions with the Mac OS X Disk Utility program and
       Linux partitions with the Linux **gdisk**, **sgdisk**, or GNU Parted programs.

       Upon start, **sgdisk** attempts to identify the partition type in use on the disk.  If  it  finds
       valid  GPT  data, **sgdisk** will use it. If **sgdisk** finds a valid MBR or BSD disklabel but no GPT
       data, it will attempt to convert the MBR or disklabel into  GPT  form.  (BSD  disklabels  are
       likely  to have unusable first and/or final partitions because they overlap with the GPT data
       structures, though.) GPT fdisk can identify, but not use data in, Apple Partition  Map  (APM)
       disks, which are used on 680x0- and PowerPC-based Macintoshes. If you specify any option that
       results in changes to an MBR or BSD disklabel, **sgdisk** ignores those  changes  unless  the  _-g_
       (_--mbrtogpt_),  _-z_ (_--zap_), or _-Z_ (_--zap-all_) option is used. If you use the _-g_ option, **sgdisk**
       replaces the MBR or disklabel with a GPT. _This_ _action_ _is_ _potentially_ _dangerous!_  Your  system
       may  become unbootable, and partition type codes may become corrupted if the disk uses unrec‐
       ognized type codes. Boot problems are particularly likely if you're  multi-booting  with  any
       GPT-unaware OS.

       The MBR-to-GPT conversion will leave at least one gap in the partition numbering if the orig‐
       inal MBR used logical partitions. These gaps are harmless, but you can eliminate them by  us‐
       ing  the  _-s_  (_--sort_)  option,  if  you  like.  (Doing  this  may require you to update your
       _/etc/fstab_ file.)

       When creating a fresh partition table, certain considerations may be in order:


       *****      For data (non-boot) disks, and for boot disks used on BIOS-based computers  with  GRUB
              as  the boot loader, partitions may be created in whatever order and in whatever sizes
              are desired.


       *****      Boot disks for EFI-based systems require an _EFI_ _System_ _Partition_ (**gdisk** internal  code
              0xEF00)  formatted  as  FAT-32.  I recommended making this partition 550 MiB. (Smaller
              ESPs are common, but some EFIs have flaky FAT drivers that necessitate a larger parti‐
              tion  for  reliable  operation.)  Boot-related  files  are stored here. (Note that GNU
              Parted identifies such partitions as having the "boot flag" set.)


       *****      Some boot loaders for BIOS-based systems make use of a _BIOS_ _Boot_ _Partition_ (**gdisk**  in‐
              ternal  code  0xEF02),  in which the secondary boot loader is stored, possibly without
              the benefit of a filesystem. (GRUB2 may optionally use such a partition.) This  parti‐
              tion  can typically be quite small (roughly 32 to 200 KiB, although 1 MiB is more com‐
              mon in practice), but you should consult your boot loader documentation for details.


       *****      If Windows is to boot from a GPT disk, a partition of type _Microsoft_ _Reserved_  (**sgdisk**
              internal  code 0x0C01) is recommended. This partition should be about 128 MiB in size.
              It ordinarily follows the EFI System Partition and immediately  precedes  the  Windows
              data  partitions. (Note that GNU Parted creates all FAT partitions as this type, which
              actually makes the partition unusable for normal file storage in both Windows and  Mac
              OS X.)


       *****      Some OSes' GPT utilities create some blank space (typically 128 MiB) after each parti‐
              tion. The intent is to enable future disk utilities to use this space. Such free space
              is not required of GPT disks, but creating it may help in future disk maintenance.


## OPTIONS
       Some  options take no arguments, others take one argument (typically a partition number), and
       others take compound arguments with colon delimitation. For instance, _-n_ (_--new_) takes a par‐
       tition  number,  a  starting  sector  number,  and  an  ending sector number, as in **sgdisk** **-n**
       **2:2000:50000** **/dev/sdc**, which creates a new partition, numbered 2, starting at sector 2000  an
       ending at sector 50,000, on _/dev/sdc_.

       Unrelated  options may be combined; however, some such combinations will be nonsense (such as
       deleting a partition and then changing its GUID type code).  **sgdisk** interprets options in the
       order  in which they're entered, so effects can vary depending on order. For instance, **sgdisk**
### -s -d
       list;  but **sgdisk** **-d** **2** **-s** deletes the original partition 2 and then sorts the modified parti‐
       tion table.

       Error checking and opportunities to correct mistakes in **sgdisk** are minimal. Although the pro‐
       gram endeavors to keep the GPT data structures legal, it does not prompt for verification be‐
       fore performing its actions. Unless you require a command-line-driven program, you should use
       the  interactive  **gdisk** instead of **sgdisk**, since **gdisk** allows you to quit without saving your
       changes, should you make a mistake.

       Although **sgdisk** is based on the same partition-manipulation code as **gdisk**, **sgdisk**  implements
       fewer features than its interactive sibling. Options available in **sgdisk** are:


### -a, --set-alignment=value
              Set the sector alignment multiple. GPT fdisk aligns the start of partitions to sectors
              that are multiples of this value, which defaults to 1 MiB (2048 on disks with 512-byte
              sectors) on freshly formatted disks. This alignment value is necessary to obtain opti‐
              mum performance with Western Digital Advanced Format and similar  drives  with  larger
              physical  than  logical sector sizes, with some types of RAID arrays, and with SSD de‐
              vices.


### -A, --attributes=list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask]]
              View or set partition attributes. Use _list_ to see defined  (known)  attribute  values.
              Omit  the  partition number (and even the device filename) when using this option. The
              others require a partition number. The _show_ and _get_ options show the current attribute
              settings (all attributes or for a particular bit, respectively). The _or_, _nand_, _xor_, _=_,
              _set_, _clear_, and _toggle_ options enable you to change the attribute bit value. The  _set_,
              _clear_,  _toggle_, and _get_ options work on a bit number; the others work on a hexadecimal
              bit mask. For example, type **sgdisk** **-A** **4:set:2** **/dev/sdc** to  set  the  bit  2  attribute
              (legacy BIOS bootable) on partition 4 on _/dev/sdc_.


### -b, --backup=file
              Save partition data to a backup file. You can back up your current in-memory partition
              table to a disk file using this option. The resulting file is a binary file consisting
              of the protective MBR, the main GPT header, the backup GPT header, and one copy of the
              partition table, in that order. Note that the backup is of the current in-memory  data
              structures,  so if you launch the program, make changes, and then use this option, the
              backup will reflect your changes. If the GPT data structures are damaged,  the  backup
              may  not  accurately reflect the damaged state; instead, they will reflect GPT fdisk's
              first-pass interpretation of the GPT.


### -B, --byte-swap-name=partnum
              Swap the byte order for the name of the specified partition. Some partitioning  tools,
              including  GPT fdisk 1.0.7 and earlier, can write the partition name in the wrong byte
              order on big-endian computers, such as the IBM s390 mainframes and PowerPC-based Macs.
              This feature corrects this problem.


### -c, --change-name=partnum:name
              Change  the  GPT  name  of  a  partition. This name is encoded as a UTF-16 string, but
              proper entry and display of anything beyond basic ASCII values requires  suitable  lo‐
              cale and font support. For the most part, Linux ignores the partition name, but it may
              be important in some OSes. If you want to set a name that includes a space, enclose it
              in  quotation  marks, as in _sgdisk_ _-c_ _1:"Sample_ _Name"_ _/dev/sdb_. Note that the GPT name
              of a partition is distinct from the filesystem name, which is encoded in the  filesys‐
              tem's data structures.


### -C, --recompute-chs
              Recompute  CHS values in protective or hybrid MBR. This option can sometimes help if a
              disk utility, OS, or BIOS doesn't like the CHS values used by the  partitions  in  the
              protective or hybrid MBR. In particular, the GPT specification requires a CHS value of
              0xFFFFFF for over-8GiB partitions, but this value is technically illegal by the  usual
              standards. Some BIOSes hang if they encounter this value. This option will recompute a
              more normal CHS value -- 0xFEFFFF for over-8GiB partitions, enabling these  BIOSes  to
              boot.


### -d, --delete=partnum
              Delete  a  partition.  This action deletes the entry from the partition table but does
              not disturb the data within the sectors originally allocated to the partition  on  the
              disk.  If  a corresponding hybrid MBR partition exists, **gdisk** deletes it, as well, and
              expands any adjacent 0xEE (EFI GPT) MBR protective partition  to  fill  the  new  free
              space.


### -D, --display-alignment
              Display current sector alignment value. Partitions will be created on multiples of the
              sector value reported by this option. You can change the alignment value with  the  -a
              option.


### -e, --move-second-header
              Move  backup  GPT  data  structures  to the end of the disk. Use this option if you've
              added disks to a RAID array, thus creating a virtual disk with space that follows  the
              backup  GPT  data structures. This command moves the backup GPT data structures to the
              end of the disk, where they belong.


### -E, --end-of-largest
              Displays the sector number of the end of the largest available block of sectors on the
              disk.  A script may store this value and pass it back as part of _-n_'s option to create
              a partition. If no unallocated sectors are available, this function returns the  value
              0.


### -f, --first-in-largest
              Displays  the  sector number of the start of the largest available block of sectors on
              the disk. A script may store this value and pass it back as part  of  _-n_'s  option  to
              create a partition. If no unallocated sectors are available, this function returns the
              value 0. Note that this parameter is blind to partition alignment; when  you  actually
              create a partition, its start point might be changed from this value.


### -F, --first-aligned-in-largest
              Similar  to _-f_ (_--first-in-largest_), except returns the sector number with the current
              alignment correction applied. Use this function if you need to compute the actual par‐
              tition  start point rather than a theoretical start point or the actual start point if
              you set the alignment value to 1.


### -g, --mbrtogpt
              Convert an MBR or BSD disklabel disk to a GPT disk. As a safety measure, use  of  this
              option  is  required on MBR or BSD disklabel disks if you intend to save your changes,
              in order to prevent accidentally damaging such disks.


### -G, --randomize-guids
              Randomize the disk's GUID and all partitions' unique GUIDs (but  not  their  partition
              type  code  GUIDs).  This function may be used after cloning a disk in order to render
              all GUIDs once again unique.


### -h, --hybrid
              Create a hybrid MBR. This option takes from one to three partition numbers,  separated
              by colons, as arguments. You may optionally specify a final partition "EE" to indicate
              that the EFI GPT (type 0xEE) should be placed last in the table, otherwise it will  be
              placed first, followed by the partition(s) you specify.  Their type codes are based on
              the GPT fdisk type codes divided by 0x0100, which is usually correct for Windows  par‐
              titions. If the active/bootable flag should be set, you must do so in another program,
              such as **fdisk**. The **gdisk** program offers additional hybrid MBR creation options.


### -i, --info=partnum
              Show detailed partition information. The summary information produced by the  _-p_  com‐
              mand  necessarily  omits  many  details,  such  as the partition's unique GUID and the
              translation of **sgdisk**'s internal partition type code to a plain type name. The _-i_  op‐
              tion displays this information for a single partition.


### -j, --adjust-main-table=sector
              Adjust  the location of the main partition table. This value is normally 2, but it may
              need to be increased in some cases, such as when a system-on-chip (SoC) is  hard-coded
              to read boot code from sector 2. I recommend against adjusting this value unless doing
              so is absolutely necessary.


### -l, --load-backup=file
              Load partition data from a backup file. This option is the reverse of the  _-b_  option.
              Note  that  restoring partition data from anything but the original disk is not recom‐
              mended. This option will work even if the disk's original partition table is bad; how‐
              ever, most other options on the same command line will be ignored.


### -L, --list-types
              Display  a summary of partition types. GPT uses a GUID to identify partition types for
              particular OSes and purposes. For ease of data entry,  **sgdisk**  compresses  these  into
              two-byte  (four-digit  hexadecimal)  values  that  are related to their equivalent MBR
              codes. Specifically, the MBR code is multiplied by hexadecimal 0x0100.  For  instance,
              the  code  for Linux swap space in MBR is 0x82, and it's 0x8200 in **gdisk**. A one-to-one
              correspondence is impossible, though. Most notably, the codes for all varieties of FAT
              and NTFS partition correspond to a single GPT code (entered as 0x0700 in **sgdisk**). Some
              OSes use a single MBR code but employ many more codes in GPT. For these,  **sgdisk**  adds
              code  numbers sequentially, such as 0xa500 for a FreeBSD disklabel, 0xa501 for FreeBSD
              boot, 0xa502 for FreeBSD swap, and so on. Note that these two-byte codes are unique to
              **gdisk**  and  **sgdisk**.  This  option  does not require you to specify a valid disk device
              filename.


### -m, --gpttombr
              Convert disk from GPT to MBR form. This option takes from one to four  partition  num‐
              bers,  separated  by colons, as arguments. Their type codes are based on the GPT fdisk
              type codes divided by 0x0100. If the active/bootable flag should be set, you  must  do
              so in another program, such as **fdisk**.  The **gdisk** program offers additional MBR conver‐
              sion options. It is not possible to convert more than four partitions from GPT to  MBR
              form  or  to convert partitions that start above the 2TiB mark or that are larger than
              2TiB.


### -n, --new=partnum:start:end
              Create a new partition. You enter a partition number, starting sector, and  an  ending
              sector.  Both  start and end sectors can be specified in absolute terms as sector num‐
              bers or as  positions  measured  in  kibibytes  (K),  mebibytes  (M),  gibibytes  (G),
              tebibytes (T), or pebibytes (P); for instance, **40M** specifies a position 40MiB from the
              start of the disk. You can specify locations relative to the start or end of the spec‐
              ified default range by preceding the number by a '+' or '-' symbol, as in **+2G** to spec‐
              ify a point 2GiB after the default start sector, or **-200M** to specify  a  point  200MiB
              before  the  last  available  sector.  A start or end value of 0 specifies the default
              value, which is the start of the largest available block for the start sector and  the
              end  of  the same block for the end sector. A partnum value of 0 causes the program to
              use the first available partition number. Subsequent uses of the _-A_ (_--attributes_), _-c_
              (_--change-name_),  _-t_ (_--typecode_), and _-u_ (_--partition-guid_) options may also use _0_ to
              refer to the same partition.


### -N, --largest-new=num
              Create a new partition that fills the largest available block of space  on  the  disk.
              You can use the _-a_ (_--set-alignment_) option to adjust the alignment, if desired. A num
              value of 0 causes the program to use the first available partition number.


### -o, --clear
              Clear out all partition data. This includes GPT header  data,  all  partition  defini‐
              tions,  and  the protective MBR. Note that this operation will, like most other opera‐
              tions, fail on a damaged disk. If you want to prepare a disk you know  to  be  damaged
              for GPT use, you should first wipe it with -Z and then partition it normally. This op‐
              tion will work even if the disk's original partition table is bad; however, most other
              options on the same command line will be ignored.


### -O, --print-mbr
              Display  basic  _MBR_  partition summary data. This includes partition numbers, starting
              and ending sector numbers, partition sizes, MBR partition types codes,  and  partition
              names.  This option is useful mainly for diagnosing partition table problems, particu‐
              larly on disks with hybrid MBRs.


### -p, --print
              Display basic GPT partition summary data. This includes  partition  numbers,  starting
              and ending sector numbers, partition sizes, **sgdisk**'s partition types codes, and parti‐
              tion names. For additional information, use the _-i_ (_--info_) option.


### -P, --pretend
              Pretend to make specified changes. In-memory GPT data structures are altered according
              to other parameters, but changes are not written to disk.


### -r, --transpose
              Swap  two  partitions'  entries  in the partition table. One or both partitions may be
              empty, although swapping two empty partitions is pointless. For  instance,  if  parti‐
              tions 1-4 are defined, transposing 1 and 5 results in a table with partitions numbered
              from 2-5. Transposing partitions in this way has no effect on their disk space alloca‐
              tion; it only alters their order in the partition table.


### -R, --replicate=second
              Replicate the main device's partition table on the specified second device.  Note that
              the replicated partition table is an exact copy, including all GUIDs;  if  the  device
              should have its own unique GUIDs, you should use the -G option on the new disk.


### -s, --sort
              Sort  partition  entries. GPT partition numbers need not match the order of partitions
              on the disk. If you want them to match, you can use this option.  Note that some  par‐
              titioning  utilities  sort partitions whenever they make changes. Such changes will be
              reflected in your device filenames, so you may need to edit _/etc/fstab_ if you use this
              option.


### -t, --typecode=partnum:{hexcode|GUID}
              Change a single partition's type code. You enter the type code using either a two-byte
              hexadecimal number, as described earlier, or a fully-specified  GUID  value,  such  as
              EBD0A0A2-B9E5-4433-87C0-68B6B72699C7.


### -T, --transform-bsd=partnum
              Transform BSD partitions into GPT partitions. This option works on BSD disklabels held
              within GPT (or converted MBR) partitions. Converted partitions' type codes are  likely
              to need manual adjustment. **sgdisk** will attempt to convert BSD disklabels stored on the
              main disk when launched, but this conversion is likely to produce  first  and/or  last
              partitions  that  are  unusable.  The  many BSD variants means that the probability of
              **sgdisk** being unable to convert a BSD disklabel is high compared to the  likelihood  of
              problems with an MBR conversion.


### -u, --partition-guid=partnum:guid
              Set  the partition unique GUID for an individual partition. The GUID may be a complete
              GUID or 'R' to set a random GUID.


### -U, --disk-guid=guid
              Set the GUID for the disk. The GUID may be a complete GUID or  'R'  to  set  a  random
              GUID.


### --usage
              Print a brief summary of available options.


### -v, --verify
              Verify  disk. This option checks for a variety of problems, such as incorrect CRCs and
              mismatched main and backup data. This option does not automatically correct most prob‐
              lems, though; for that, you must use options on the recovery & transformation menu. If
              no problems are found, this command displays a summary of unallocated disk space. This
              option  will  work  even  if the disk's original partition table is bad; however, most
              other options on the same command line will be ignored.


### -V, --version
              Display program version information. This option may be used without specifying a  de‐
              vice filename.


### -z, --zap
              Zap  (destroy)  the  GPT data structures and then exit. Use this option if you want to
              repartition a GPT disk using **fdisk** or some other GPT-unaware program. This option  de‐
              stroys  only  the  GPT data structures; it leaves the MBR intact. This makes it useful
              for wiping out GPT data structures after a disk has been repartitioned for MBR using a
              GPT-unaware  utility; however, there's a risk that it will damage boot loaders or even
              the start of the first or end of the last MBR partition. If you use it on a valid  GPT
              disk,  the MBR will be left with an inappropriate EFI GPT (0xEE) partition definition,
              which you can delete using another utility.


### -Z, --zap-all
              Zap (destroy) the GPT and MBR data structures and then exit. This  option  works  much
              like _-z_, but as it wipes the MBR as well as the GPT, it's more suitable if you want to
              repartition a disk after using this option, and completely unsuitable  if  you've  al‐
              ready repartitioned the disk.


### -?, --help
              Print a summary of options.


## RETURN VALUES
       **sgdisk** returns various values depending on its success or failure:


       **0**      Normal program execution


       **1**      Too few arguments


       **2**      An error occurred while reading the partition table


       **3**      Non-GPT disk detected and no _-g_ option, but operation requires a write action


       **4**      An error prevented saving changes


       **5**      An  error  occurred  while reading standard input (should never occur with sgdisk, but
              may with gdisk)


       **8**      Disk replication operation (-R) failed


## BUGS
       Known bugs and limitations include:


       *****      The program compiles correctly only on Linux, FreeBSD, and Mac OS  X.  Linux  versions
              for  x86-64  (64-bit),  x86  (32-bit), and PowerPC (32-bit) have been tested, with the
              x86-64 version having seen the most testing.


       *****      The FreeBSD version of the program can't write changes to the  partition  table  to  a
              disk  when existing partitions on that disk are mounted. (The same problem exists with
              many other FreeBSD utilities, such as **gpt**, **fdisk**, and  **dd**.)  This  limitation  can  be
              overcome by typing **sysctl** **kern.geom.debugflags=16** at a shell prompt.


       *****      The  fields  used to display the start and end sector numbers for partitions in the _-p_
              option are 14 characters wide. This translates to a limitation of  about  45  PiB.  On
              larger disks, the displayed columns will go out of alignment.


       *****      The  program  can load only up to 128 partitions (4 primary partitions and 124 logical
              partitions) when converting from MBR format. This limit can be raised by changing  the
              _#define_  _MAX_MBR_PARTS_  line  in the _basicmbr.h_ source code file and recompiling; how‐
              ever, such a change will require using  a  larger-than-normal  partition  table.  (The
              limit  of 128 partitions was chosen because that number equals the 128 partitions sup‐
              ported by the most common partition table size.)


       *****      Converting from MBR format sometimes fails because of insufficient space at the  start
              or  (more  commonly)  the end of the disk. Resizing the partition table (using the 's'
              option in the experts' menu) can sometimes overcome this problem; however, in  extreme
              cases  it  may  be  necessary to resize a partition using GNU Parted or a similar tool
              prior to conversion with **gdisk**.


       *****      MBR conversions work only if the disk has correct LBA partition descriptors. These de‐
              scriptors  should be present on any disk over 8 GiB in size or on smaller disks parti‐
              tioned with any but very ancient software.


       *****      BSD disklabel support can create first and/or last partitions that  overlap  with  the
              GPT  data structures. This can sometimes be compensated by adjusting the partition ta‐
              ble size, but in extreme cases the affected partition(s) may need to be deleted.


       *****      Because of the highly variable nature of BSD disklabel  structures,  conversions  from
              this form may be unreliable -- partitions may be dropped, converted in a way that cre‐
              ates overlaps with other partitions, or converted with incorrect start or end  values.
              Use this feature with caution!


       *****      Booting after converting an MBR or BSD disklabel disk is likely to be disrupted. Some‐
              times re-installing a boot loader will fix the problem, but other times you  may  need
              to  switch  boot loaders. Except on EFI-based platforms, Windows through at least Win‐
              dows 7 RC doesn't support booting from GPT disks. Creating a hybrid MBR (using the 'h'
              option on the recovery & transformation menu) or abandoning GPT in favor of MBR may be
              your only options in this case.


## AUTHORS
       Primary author: Roderick W. Smith (<rodsmith@rodsbooks.com>)

       Contributors:

       * Yves Blusseau (<1otnwmz02@sneakemail.com>)

       * David Hubbard (<david.c.hubbard@gmail.com>)

       * Justin Maggard (<justin.maggard@netgear.com>)

       * Dwight Schauer (<das@teegra.net>)

       * Florian Zumbiehl (<florz@florz.de>)



## SEE ALSO
       [**cfdisk**(8)](https://www.chedong.com/phpMan.php/man/cfdisk/8/markdown), [**cgdisk**(8)](https://www.chedong.com/phpMan.php/man/cgdisk/8/markdown), [**fdisk**(8)](https://www.chedong.com/phpMan.php/man/fdisk/8/markdown), [**gdisk**(8)](https://www.chedong.com/phpMan.php/man/gdisk/8/markdown), [**mkfs**(8)](https://www.chedong.com/phpMan.php/man/mkfs/8/markdown), [**parted**(8)](https://www.chedong.com/phpMan.php/man/parted/8/markdown), [**sfdisk**(8)](https://www.chedong.com/phpMan.php/man/sfdisk/8/markdown), [**fixparts**(8)](https://www.chedong.com/phpMan.php/man/fixparts/8/markdown).

       _<http://en.wikipedia.org/wiki/GUID_Partition_Table_>

       _<http://developer.apple.com/technotes/tn2006/tn2166.html_>

       _<http://www.rodsbooks.com/gdisk/_>


## AVAILABILITY
       The **sgdisk** command is part of the _GPT_ _fdisk_ package and is available from Rod Smith.



Roderick W. Smith                               1.0.8                                      [SGDISK(8)](https://www.chedong.com/phpMan.php/man/SGDISK/8/markdown)
