GPART(8) FreeBSD System Manager's Manual GPART(8)
NAME
gpart - control utility for the disk partitioning GEOM class
SYNOPSIS
gpart add -t type [-a alignment] [-b start] [-s size] [-i index]
[-l label] [-f flags] geom
gpart backup geom
gpart bootcode [-N] [-b bootcode] [-p partcode -i index] [-f flags] geom
gpart commit geom
gpart create -s scheme [-n entries] [-f flags] provider
gpart delete -i index [-f flags] geom
gpart destroy [-F] [-f flags] geom
gpart modify -i index [-l label] [-t type] [-f flags] geom
gpart recover [-f flags] geom
gpart resize -i index [-a alignment] [-s size] [-f flags] geom
gpart restore [-lF] [-f flags] provider [...]
gpart set -a attrib -i index [-f flags] geom
gpart [--libxo] show [-l | -r] [-p] [geom ...]
gpart undo geom
gpart unset -a attrib -i index [-f flags] geom
gpart list
gpart status
gpart load
gpart unload
DESCRIPTION
The gpart utility is used to partition GEOM providers, normally disks.
The first argument is the action to be taken:
add Add a new partition to the partitioning scheme given by geom.
The partition type must be specified with -t type. The
partition's location, size, and other attributes will be
calculated automatically if the corresponding options are not
specified.
The add command accepts these options:
-a alignment If specified, then the gpart utility tries to
align start offset and partition size to be
multiple of alignment value.
-b start The logical block address where the partition
will begin. A single-character suffix (k, m, g,
etc.) is allowed to specify binary byte sizes.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index The index in the partition table at which the new
partition is to be placed. The index determines
the name of the device special file used to
represent the partition.
-l label The label attached to the partition. This option
is only valid when used on partitioning schemes
that support partition labels.
-s size Create a partition of size size. A single-
character suffix (k, m, g, etc.) is allowed to
specify binary byte sizes.
-t type Create a partition of type type. Partition types
are discussed below in the section entitled
PARTITION TYPES.
backup Dump a partition table to standard output in a special format
used by the restore action.
bootcode Embed bootstrap code into the partitioning scheme's metadata on
the geom (using -b bootcode) or write bootstrap code into a
partition (using -p partcode and -i index).
The bootcode command accepts these options:
-N Do not preserve the Volume Serial Number for MBR.
MBR bootcode contains Volume Serial Number by
default, and gpart tries to preserve it when
installing new bootstrap code. This option skips
preservation to help with some versions of
boot0cfg(8) that do not support Volume Serial
Number.
-b bootcode
Embed bootstrap code from the file bootcode into
the partitioning scheme's metadata for geom. Not
all partitioning schemes have embedded bootstrap
code, so the -b bootcode option is scheme-specific
in nature (see the section entitled BOOTSTRAPPING
below). The bootcode file must match the
partitioning scheme's requirements for file content
and size.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specify the target partition for -p partcode.
-p partcode
Write the bootstrap code from the file partcode
into the geom partition specified by -i index. The
size of the file must be smaller than the size of
the partition.
commit Commit any pending changes for geom geom. All actions are
committed by default and will not result in pending changes.
Actions can be modified with the -f flags option so that they
are not committed, but become pending. Pending changes are
reflected by the geom and the gpart utility, but they are not
actually written to disk. The commit action will write all
pending changes to disk.
create Create a new partitioning scheme on a provider given by
provider. The scheme to use must be specified with the -s
scheme option.
The create command accepts these options:
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-n entries The number of entries in the partition table.
Every partitioning scheme has a minimum and maximum
number of entries. This option allows tables to be
created with a number of entries that is within the
limits. Some schemes have a maximum equal to the
minimum and some schemes have a maximum large
enough to be considered unlimited. By default,
partition tables are created with the minimum
number of entries.
-s scheme Specify the partitioning scheme to use. The kernel
must have support for a particular scheme before
that scheme can be used to partition a disk.
delete Delete a partition from geom geom and further identified by the
-i index option. The partition cannot be actively used by the
kernel.
The delete command accepts these options:
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specifies the index of the partition to be deleted.
destroy Destroy the partitioning scheme as implemented by geom geom.
The destroy command accepts these options:
-F Forced destroying of the partition table even if it
is not empty.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
modify Modify a partition from geom geom and further identified by the
-i index option. Only the type and/or label of the partition
can be modified. Not all partitioning schemes support labels
and it is invalid to try to change a partition label in such
cases.
The modify command accepts these options:
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specifies the index of the partition to be
modified.
-l label Change the partition label to label.
-t type Change the partition type to type.
recover Recover a corrupt partition's scheme metadata on the geom geom.
See the section entitled RECOVERING below for the additional
information.
The recover command accepts these options:
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
resize Resize a partition from geom geom and further identified by the
-i index option. If the new size is not specified it is
automatically calculated to be the maximum available from geom.
The resize command accepts these options:
-a alignment If specified, then the gpart utility tries to
align partition size to be a multiple of the
alignment value.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specifies the index of the partition to be
resized.
-s size Specifies the new size of the partition, in
logical blocks, or binary byte sizes if a single-
character suffix (k, m, g, etc.) is provided.
restore Restore the partition table from a backup previously created by
the backup action and read from standard input. Only the
partition table is restored. This action does not affect the
content of partitions. After restoring the partition table and
writing bootcode if needed, user data must be restored from
backup.
The restore command accepts these options:
-F Destroy partition table on the given provider
before doing restore.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-l Restore partition labels for partitioning schemes
that support them.
set Set the named attribute on the partition entry. See the
section entitled ATTRIBUTES below for a list of available
attributes.
The set command accepts these options:
-a attrib Specifies the attribute to set.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specifies the index of the partition on which the
attribute will be set.
show Show current partition information for the specified geoms, or
all geoms if none are specified. The default output includes
the logical starting block of each partition, the partition
size in blocks, the partition index number, the partition type,
and a human readable partition size. Block sizes and locations
are based on the device's Sectorsize as shown by gpart list.
The show command accepts these options:
-l For partitioning schemes that support partition
labels, print them instead of partition type.
-p Show provider names instead of partition indexes.
-r Show raw partition type instead of symbolic name.
undo Revert any pending changes for geom geom. This action is the
opposite of the commit action and can be used to undo any
changes that have not been committed.
unset Clear the named attribute on the partition entry. See the
section entitled ATTRIBUTES below for a list of available
attributes.
The unset command accepts these options:
-a attrib Specifies the attribute to clear.
-f flags Additional operational flags. See the section
entitled OPERATIONAL FLAGS below for a discussion
about its use.
-i index Specifies the index of the partition on which the
attribute will be cleared.
list See geom(8).
status See geom(8).
load See geom(8).
unload See geom(8).
--libxo Generate output via libxo(3) in a selection of different human
and machine readable formats. See xo_options(7) for details on
command line arguments.
PARTITIONING SCHEMES
Several partitioning schemes are supported by the gpart utility:
APM Apple Partition Map, used by PowerPC(R) Macintosh(R) computers.
Requires the GEOM_PART_APM kernel option.
BSD Traditional BSD disklabel(8), usually used to subdivide MBR
partitions. (This scheme can also be used as the sole
partitioning method, without an MBR. Partition editing tools from
other operating systems often do not understand the bare disklabel
partition layout, so this is sometimes called "dangerously
dedicated".) Requires the GEOM_PART_BSD kernel option.
BSD64 64-bit implementation of BSD disklabel used in DragonFly to
subdivide MBR or GPT partitions. Requires the GEOM_PART_BSD64
kernel option.
LDM The Logical Disk Manager is an implementation of volume manager
for Microsoft Windows NT. Requires the GEOM_PART_LDM kernel
option.
GPT GUID Partition Table is used on Intel-based Macintosh computers
and gradually replacing MBR on most PCs and other systems.
Requires the GEOM_PART_GPT kernel option.
MBR Master Boot Record is used on PCs and removable media. Requires
the GEOM_PART_MBR kernel option. The GEOM_PART_EBR option adds
support for the Extended Boot Record (EBR), which is used to
define a logical partition. The GEOM_PART_EBR_COMPAT option
enables backward compatibility for partition names in the EBR
scheme. It also prevents any type of actions on such partitions.
See glabel(8) for additional information on labelization of devices and
partitions.
PARTITION TYPES
Partition types are identified on disk by particular strings or magic
values. The gpart utility uses symbolic names for common partition types
so the user does not need to know these values or other details of the
partitioning scheme in question. The gpart utility also allows the user
to specify scheme-specific partition types for partition types that do
not have symbolic names. Symbolic names currently understood and used by
FreeBSD are:
apple-boot The system partition dedicated to storing boot
loaders on some Apple systems. The scheme-
specific types are "!171" for MBR,
"!Apple_Bootstrap" for APM, and
"!426f6f74-0000-11aa-aa11-00306543ecac" for GPT.
bios-boot The system partition dedicated to second stage of
the boot loader program. Usually it is used by
the GRUB 2 loader for GPT partitioning schemes.
The scheme-specific type is
"!21686148-6449-6E6F-744E-656564454649".
efi The system partition for computers that use the
Extensible Firmware Interface (EFI). The scheme-
specific types are "!239" for MBR, and
"!c12a7328-f81f-11d2-ba4b-00a0c93ec93b" for GPT.
freebsd A FreeBSD partition subdivided into filesystems
with a BSD disklabel. This is a legacy partition
type and should not be used for the APM or GPT
schemes. The scheme-specific types are "!165" for
MBR, "!FreeBSD" for APM, and
"!516e7cb4-6ecf-11d6-8ff8-00022d09712b" for GPT.
freebsd-boot A FreeBSD partition dedicated to bootstrap code.
The scheme-specific type is
"!83bd6b9d-7f41-11dc-be0b-001560b84f0f" for GPT.
freebsd-swap A FreeBSD partition dedicated to swap space. The
scheme-specific types are "!FreeBSD-swap" for APM,
and "!516e7cb5-6ecf-11d6-8ff8-00022d09712b" for
GPT.
freebsd-ufs A FreeBSD partition that contains a UFS or UFS2
filesystem. The scheme-specific types are
"!FreeBSD-UFS" for APM, and
"!516e7cb6-6ecf-11d6-8ff8-00022d09712b" for GPT.
freebsd-zfs A FreeBSD partition that contains a ZFS volume.
The scheme-specific types are "!FreeBSD-ZFS" for
APM, and "!516e7cba-6ecf-11d6-8ff8-00022d09712b"
for GPT.
Other symbolic names that can be used with the gpart utility are:
apple-apfs An Apple macOS partition used for the Apple file
system, APFS.
apple-core-storage An Apple Mac OS X partition used by logical volume
manager known as Core Storage. The scheme-
specific type is
"!53746f72-6167-11aa-aa11-00306543ecac" for GPT.
apple-hfs An Apple Mac OS X partition that contains a HFS or
HFS+ filesystem. The scheme-specific types are
"!175" for MBR, "!Apple_HFS" for APM and
"!48465300-0000-11aa-aa11-00306543ecac" for GPT.
apple-label An Apple Mac OS X partition dedicated to partition
metadata that descibes disk device. The scheme-
specific type is
"!4c616265-6c00-11aa-aa11-00306543ecac" for GPT.
apple-raid An Apple Mac OS X partition used in a software
RAID configuration. The scheme-specific type is
"!52414944-0000-11aa-aa11-00306543ecac" for GPT.
apple-raid-offline An Apple Mac OS X partition used in a software
RAID configuration. The scheme-specific type is
"!52414944-5f4f-11aa-aa11-00306543ecac" for GPT.
apple-tv-recovery An Apple Mac OS X partition used by Apple TV. The
scheme-specific type is
"!5265636f-7665-11aa-aa11-00306543ecac" for GPT.
apple-ufs An Apple Mac OS X partition that contains a UFS
filesystem. The scheme-specific types are "!168"
for MBR, "!Apple_UNIX_SVR2" for APM and
"!55465300-0000-11aa-aa11-00306543ecac" for GPT.
apple-zfs An Apple Mac OS X partition that contains a ZFS
volume. The scheme-specific type is
"!6a898cc3-1dd2-11b2-99a6-080020736631" for GPT.
The same GUID is being used also for
illumos/Solaris /usr partition. See CAVEATS
section below.
dragonfly-label32 A DragonFly partition subdivided into filesystems
with a BSD disklabel. The scheme-specific type is
"!9d087404-1ca5-11dc-8817-01301bb8a9f5" for GPT.
dragonfly-label64 A DragonFly partition subdivided into filesystems
with a disklabel64. The scheme-specific type is
"!3d48ce54-1d16-11dc-8696-01301bb8a9f5" for GPT.
dragonfly-legacy A legacy partition type used in DragonFly. The
scheme-specific type is
"!bd215ab2-1d16-11dc-8696-01301bb8a9f5" for GPT.
dragonfly-ccd A DragonFly partition used with Concatenated Disk
driver. The scheme-specific type is
"!dbd5211b-1ca5-11dc-8817-01301bb8a9f5" for GPT.
dragonfly-hammer A DragonFly partition that contains a Hammer
filesystem. The scheme-specific type is
"!61dc63ac-6e38-11dc-8513-01301bb8a9f5" for GPT.
dragonfly-hammer2 A DragonFly partition that contains a Hammer2
filesystem. The scheme-specific type is
"!5cbb9ad1-862d-11dc-a94d-01301bb8a9f5" for GPT.
dragonfly-swap A DragonFly partition dedicated to swap space.
The scheme-specific type is
"!9d58fdbd-1ca5-11dc-8817-01301bb8a9f5" for GPT.
dragonfly-ufs A DragonFly partition that contains an UFS1
filesystem. The scheme-specific type is
"!9d94ce7c-1ca5-11dc-8817-01301bb8a9f5" for GPT.
dragonfly-vinum A DragonFly partition used with Logical Volume
Manager. The scheme-specific type is
"!9dd4478f-1ca5-11dc-8817-01301bb8a9f5" for GPT.
ebr A partition subdivided into filesystems with a
EBR. The scheme-specific type is "!5" for MBR.
fat16 A partition that contains a FAT16 filesystem. The
scheme-specific type is "!6" for MBR.
fat32 A partition that contains a FAT32 filesystem. The
scheme-specific type is "!11" for MBR.
fat32lba A partition that contains a FAT32 (LBA)
filesystem. The scheme-specific type is "!12" for
MBR.
hifive-fsbl A raw partition containing a HiFive first stage
bootloader. The scheme-specific type is
"!5b193300-fc78-40cd-8002-e86c45580b47" for GPT.
hifive-bbl A raw partition containing a HiFive second stage
bootloader. The scheme-specific type is
"!2e54b353-1271-4842-806f-e436d6af6985" for GPT.
linux-data A Linux partition that contains some filesystem
with data. The scheme-specific types are "!131"
for MBR and
"!0fc63daf-8483-4772-8e79-3d69d8477de4" for GPT.
linux-lvm A Linux partition dedicated to Logical Volume
Manager. The scheme-specific types are "!142" for
MBR and "!e6d6d379-f507-44c2-a23c-238f2a3df928"
for GPT.
linux-raid A Linux partition used in a software RAID
configuration. The scheme-specific types are
"!253" for MBR and
"!a19d880f-05fc-4d3b-a006-743f0f84911e" for GPT.
linux-swap A Linux partition dedicated to swap space. The
scheme-specific types are "!130" for MBR and
"!0657fd6d-a4ab-43c4-84e5-0933c84b4f4f" for GPT.
mbr A partition that is sub-partitioned by a Master
Boot Record (MBR). This type is known as
"!024dee41-33e7-11d3-9d69-0008c781f39f" by GPT.
ms-basic-data A basic data partition (BDP) for Microsoft
operating systems. In the GPT this type is the
equivalent to partition types fat16, fat32 and
ntfs in MBR. This type is used for GPT exFAT
partitions. The scheme-specific type is
"!ebd0a0a2-b9e5-4433-87c0-68b6b72699c7" for GPT.
ms-ldm-data A partition that contains Logical Disk Manager
(LDM) volumes. The scheme-specific types are
"!66" for MBR,
"!af9b60a0-1431-4f62-bc68-3311714a69ad" for GPT.
ms-ldm-metadata A partition that contains Logical Disk Manager
(LDM) database. The scheme-specific type is
"!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3" for GPT.
netbsd-ccd A NetBSD partition used with Concatenated Disk
driver. The scheme-specific type is
"!2db519c4-b10f-11dc-b99b-0019d1879648" for GPT.
netbsd-cgd An encrypted NetBSD partition. The scheme-
specific type is
"!2db519ec-b10f-11dc-b99b-0019d1879648" for GPT.
netbsd-ffs A NetBSD partition that contains an UFS
filesystem. The scheme-specific type is
"!49f48d5a-b10e-11dc-b99b-0019d1879648" for GPT.
netbsd-lfs A NetBSD partition that contains an LFS
filesystem. The scheme-specific type is
"!49f48d82-b10e-11dc-b99b-0019d1879648" for GPT.
netbsd-raid A NetBSD partition used in a software RAID
configuration. The scheme-specific type is
"!49f48daa-b10e-11dc-b99b-0019d1879648" for GPT.
netbsd-swap A NetBSD partition dedicated to swap space. The
scheme-specific type is
"!49f48d32-b10e-11dc-b99b-0019d1879648" for GPT.
ntfs A partition that contains a NTFS or exFAT
filesystem. The scheme-specific type is "!7" for
MBR.
prep-boot The system partition dedicated to storing boot
loaders on some PowerPC systems, notably those
made by IBM. The scheme-specific types are "!65"
for MBR and
"!9e1a2d38-c612-4316-aa26-8b49521e5a8b" for GPT.
solaris-boot A illumos/Solaris partition dedicated to boot
loader. The scheme-specific type is
"!6a82cb45-1dd2-11b2-99a6-080020736631" for GPT.
solaris-root A illumos/Solaris partition dedicated to root
filesystem. The scheme-specific type is
"!6a85cf4d-1dd2-11b2-99a6-080020736631" for GPT.
solaris-swap A illumos/Solaris partition dedicated to swap.
The scheme-specific type is
"!6a87c46f-1dd2-11b2-99a6-080020736631" for GPT.
solaris-backup A illumos/Solaris partition dedicated to backup.
The scheme-specific type is
"!6a8b642b-1dd2-11b2-99a6-080020736631" for GPT.
solaris-var A illumos/Solaris partition dedicated to /var
filesystem. The scheme-specific type is
"!6a8ef2e9-1dd2-11b2-99a6-080020736631" for GPT.
solaris-home A illumos/Solaris partition dedicated to /home
filesystem. The scheme-specific type is
"!6a90ba39-1dd2-11b2-99a6-080020736631" for GPT.
solaris-altsec A illumos/Solaris partition dedicated to alternate
sector. The scheme-specific type is
"!6a9283a5-1dd2-11b2-99a6-080020736631" for GPT.
solaris-reserved A illumos/Solaris partition dedicated to reserved
space. The scheme-specific type is
"!6a945a3b-1dd2-11b2-99a6-080020736631" for GPT.
u-boot-env A raw partition dedicated to U-Boot for storing
its environment. The scheme-specific type is
"!3de21764-95bd-54bd-a5c3-4abe786f38a8" for GPT.
vmware-vmfs A partition that contains a VMware File System
(VMFS). The scheme-specific types are "!251" for
MBR and "!aa31e02a-400f-11db-9590-000c2911d1b8"
for GPT.
vmware-vmkdiag A partition that contains a VMware diagostic
filesystem. The scheme-specific types are "!252"
for MBR and
"!9d275380-40ad-11db-bf97-000c2911d1b8" for GPT.
vmware-reserved A VMware reserved partition. The scheme-specific
type is "!9198effc-31c0-11db-8f-78-000c2911d1b8"
for GPT.
vmware-vsanhdr A partition claimed by VMware VSAN. The scheme-
specific type is
"!381cfccc-7288-11e0-92ee-000c2911d0b2" for GPT.
xbootldr An Extended Boot Loader Partition (XBOOTLDR),
secondary to the EFI system partition, used to
store additional firmware or boot loader menu
entries. The scheme-specific type is
"!bc13c2ff-59e6-4262-a352-b275fd6f7172" for GPT.
ATTRIBUTES
The scheme-specific attributes for EBR:
active
The scheme-specific attributes for GPT:
bootme When set, the gptboot stage 1 boot loader will try to boot
the system from this partition. Multiple partitions can be
marked with the bootme attribute. See gptboot(8) for more
details.
bootonce Setting this attribute automatically sets the bootme
attribute. When set, the gptboot stage 1 boot loader will
try to boot the system from this partition only once.
Multiple partitions can be marked with the bootonce and
bootme attribute pairs. See gptboot(8) for more details.
bootfailed This attribute should not be manually managed. It is managed
by the gptboot stage 1 boot loader and the /etc/rc.d/gptboot
start-up script. See gptboot(8) for more details.
lenovofix Setting this attribute overwrites the Protective MBR with a
new one where the 0xee partition is the second, rather than
the first record. This resolves a BIOS compatibility issue
with some Lenovo models including the X220, T420, and T520,
allowing them to boot from GPT partitioned disks without
using EFI.
The scheme-specific attributes for MBR:
active
BOOTSTRAPPING
FreeBSD supports several partitioning schemes and each scheme uses
different bootstrap code. The bootstrap code is located in a specific
disk area for each partitioning scheme, and may vary in size for
different schemes.
Bootstrap code can be separated into two types. The first type is
embedded in the partitioning scheme's metadata, while the second type is
located on a specific partition. Embedding bootstrap code should only be
done with the gpart bootcode command with the -b bootcode option. The
GEOM PART class knows how to safely embed bootstrap code into specific
partitioning scheme metadata without causing any damage.
The Master Boot Record (MBR) uses a 512-byte bootstrap code image,
embedded into the partition table's metadata area. There are two
variants of this bootstrap code: /boot/mbr and /boot/boot0. /boot/mbr
searches for a partition with the active attribute (see the ATTRIBUTES
section) in the partition table. Then it runs next bootstrap stage. The
/boot/boot0 image contains a boot manager with some additional
interactive functions for multi-booting from a user-selected partition.
A BSD disklabel is usually created inside an MBR partition (slice) with
type freebsd (see the PARTITION TYPES section). It uses 8 KiB size
bootstrap code image /boot/boot, embedded into the partition table's
metadata area.
Both types of bootstrap code are used to boot from the GUID Partition
Table. First, a protective MBR is embedded into the first disk sector
from the /boot/pmbr image. It searches through the GPT for a
freebsd-boot partition (see the PARTITION TYPES section) and runs the
next bootstrap stage from it. The freebsd-boot partition should be
smaller than 545 KiB. It can be located either before or after other
FreeBSD partitions on the disk. There are two variants of bootstrap code
to write to this partition: /boot/gptboot and /boot/gptzfsboot.
/boot/gptboot is used to boot from UFS partitions. gptboot searches
through freebsd-ufs partitions in the GPT and selects one to boot based
on the bootonce and bootme attributes. If neither attribute is found,
/boot/gptboot boots from the first freebsd-ufs partition. /boot/loader
(the third bootstrap stage) is loaded from the first partition that
matches these conditions. See gptboot(8) for more information.
/boot/gptzfsboot is used to boot from ZFS. It searches through the GPT
for freebsd-zfs partitions, trying to detect ZFS pools. After all pools
are detected, /boot/loader is started from the first one found set as
bootable.
The APM scheme also does not support embedding bootstrap code. Instead,
the 800 KiB bootstrap code image /boot/boot1.hfs should be written with
the gpart bootcode command to a partition of type apple-boot, which
should also be 800 KiB in size.
OPERATIONAL FLAGS
Actions other than the commit and undo actions take an optional -f flags
option. This option is used to specify action-specific operational
flags. By default, the gpart utility defines the `C' flag so that the
action is immediately committed. The user can specify "-f x" to have the
action result in a pending change that can later, with other pending
changes, be committed as a single compound change with the commit action
or reverted with the undo action.
RECOVERING
The GEOM PART class supports recovering of partition tables only for GPT.
The GPT primary metadata is stored at the beginning of the device. For
redundancy, a secondary (backup) copy of the metadata is stored at the
end of the device. As a result of having two copies, some corruption of
metadata is not fatal to the working of GPT. When the kernel detects
corrupt metadata, it marks this table as corrupt and reports the problem.
destroy and recover are the only operations allowed on corrupt tables.
If one GPT header appears to be corrupt but the other copy remains
intact, the kernel will log the following:
GEOM: provider: the primary GPT table is corrupt or invalid.
GEOM: provider: using the secondary instead -- recovery strongly advised.
or
GEOM: provider: the secondary GPT table is corrupt or invalid.
GEOM: provider: using the primary only -- recovery suggested.
Also gpart commands such as show, status and list will report about
corrupt tables.
If the size of the device has changed (e.g., volume expansion) the
secondary GPT header will no longer be located in the last sector. This
is not a metadata corruption, but it is dangerous because any corruption
of the primary GPT will lead to loss of the partition table. This
problem is reported by the kernel with the message:
GEOM: provider: the secondary GPT header is not in the last LBA.
This situation can be recovered with the recover command. This command
reconstructs the corrupt metadata using known valid metadata and
relocates the secondary GPT to the end of the device.
NOTE: The GEOM PART class can detect the same partition table visible
through different GEOM providers, and some of them will be marked as
corrupt. Be careful when choosing a provider for recovery. If you
choose incorrectly you can destroy the metadata of another GEOM class,
e.g., GEOM MIRROR or GEOM LABEL.
SYSCTL VARIABLES
The following sysctl(8) variables can be used to control the behavior of
the PART GEOM class. The default value is shown next to each variable.
kern.geom.part.allow_nesting: 0
By default, some schemes (currently BSD and BSD64) do not permit
further nested partitioning. This variable overrides this
restriction and allows arbitrary nesting (except within
partitions created at offset 0). Some schemes have their own
separate checks, for which see below.
kern.geom.part.auto_resize: 1
This variable controls automatic resize behavior of the PART GEOM
class. When this variable is enable and new size of provider is
detected, the schema metadata is resized but all changes are not
saved to disk, until gpart commit is run to confirm changes.
This behavior is also reported with diagnostic message:
GEOM_PART: (provider) was automatically resized. Use `gpart
commit (provider)` to save changes or `gpart undo (provider)` to
revert them.
kern.geom.part.check_integrity: 1
This variable controls the behaviour of metadata integrity
checks. When integrity checks are enabled, the PART GEOM class
verifies all generic partition parameters obtained from the disk
metadata. If some inconsistency is detected, the partition table
will be rejected with a diagnostic message: GEOM_PART: Integrity
check failed (provider, scheme).
kern.geom.part.gpt.allow_nesting: 0
By default the GPT scheme is allowed only at the outermost
nesting level. This variable allows this restriction to be
removed.
kern.geom.part.ldm.debug: 0
Debug level of the Logical Disk Manager (LDM) module. This can
be set to a number between 0 and 2 inclusive. If set to 0
minimal debug information is printed, and if set to 2 the maximum
amount of debug information is printed.
kern.geom.part.ldm.show_mirrors: 0
This variable controls how the Logical Disk Manager (LDM) module
handles mirrored volumes. By default mirrored volumes are shown
as partitions with type ms-ldm-data (see the PARTITION TYPES
section). If this variable set to 1 each component of the
mirrored volume will be present as independent partition. NOTE:
This may break a mirrored volume and lead to data damage.
kern.geom.part.mbr.enforce_chs: 0
Specify how the Master Boot Record (MBR) module does alignment.
If this variable is set to a non-zero value, the module will
automatically recalculate the user-specified offset and size for
alignment with the CHS geometry. Otherwise the values will be
left unchanged.
kern.geom.part.separator:
Specify an optional separator that will be inserted between the
GEOM name and partition name. This variable is a loader(8)
tunable. Note that setting this variable may break software
which assumes a particular naming scheme.
EXIT STATUS
Exit status is 0 on success, and 1 if the command fails.
EXAMPLES
The examples below assume that the disk's logical block size is
512 bytes, regardless of its physical block size.
GPT
In this example, we will format ada0 with the GPT scheme and create boot,
swap and root partitions. First, we need to create the partition table:
/sbin/gpart create -s GPT ada0
Next, we install a protective MBR with the first-stage bootstrap code.
The protective MBR lists a single, bootable partition spanning the entire
disk, thus allowing non-GPT-aware BIOSes to boot from the disk and
preventing tools which do not understand the GPT scheme from considering
the disk to be unformatted.
/sbin/gpart bootcode -b /boot/pmbr ada0
We then create a dedicated freebsd-boot partition to hold the second-
stage boot loader, which will load the FreeBSD kernel and modules from a
UFS or ZFS filesystem. This partition must be larger than the bootstrap
code (either /boot/gptboot for UFS or /boot/gptzfsboot for ZFS), but
smaller than 545 KiB since the first-stage loader will load the entire
partition into memory during boot, regardless of how much data it
actually contains. We create a 472-block (236 KiB) boot partition at
offset 40, which is the size of the partition table (34 blocks or 17 KiB)
rounded up to the nearest 4 KiB boundary.
/sbin/gpart add -b 40 -s 472 -t freebsd-boot ada0
/sbin/gpart bootcode -p /boot/gptboot -i 1 ada0
We now create a 4 GiB swap partition at the first available offset, which
is 40 + 472 = 512 blocks (256 KiB).
/sbin/gpart add -s 4G -t freebsd-swap ada0
Aligning the swap partition and all subsequent partitions on a 256 KiB
boundary ensures optimal performance on a wide range of media, from plain
old disks with 512-byte blocks, through modern "advanced format" disks
with 4096-byte physical blocks, to RAID volumes with stripe sizes of up
to 256 KiB.
Finally, we create and format an 8 GiB freebsd-ufs partition for the root
filesystem, leaving the rest of the device free for additional
filesystems:
/sbin/gpart add -s 8G -t freebsd-ufs ada0
/sbin/newfs -Uj /dev/ada0p3
MBR
In this example, we will format ada0 with the MBR scheme and create a
single partition which we subdivide using a traditional BSD disklabel.
First, we create the partition table as well as a single partition 64 GiB
in size and an alignment of 4 KiB, then we mark that partition active
(bootable) and install the first-stage boot loader:
/sbin/gpart create -s MBR ada0
/sbin/gpart add -t freebsd -s 64G -a 4k ada0
/sbin/gpart set -a active -i 1 ada0
/sbin/gpart bootcode -b /boot/boot0 ada0
Next, we create a disklabel in that partition ("slice" in disklabel
terminology) with room for up to 20 partitions:
/sbin/gpart create -s BSD -n 20 ada0s1
We then create an 8 GiB root partition and a 4 GiB swap partition:
/sbin/gpart add -t freebsd-ufs -s 8G ada0s1
/sbin/gpart add -t freebsd-swap -s 4G ada0s1
Finally, we install the appropriate boot loader for the BSD label:
/sbin/gpart bootcode -b /boot/boot ada0s1
Deleting Partitions and Destroying the Partitioning Scheme
If a Device busy error is shown when trying to destroy a partition table,
remember that all of the partitions must be deleted first with the delete
action. In this example, da0 has three partitions:
/sbin/gpart delete -i 3 da0
/sbin/gpart delete -i 2 da0
/sbin/gpart delete -i 1 da0
/sbin/gpart destroy da0
Rather than deleting each partition and then destroying the partitioning
scheme, the -F option can be given with destroy to delete all of the
partitions before destroying the partitioning scheme. This is equivalent
to the previous example:
/sbin/gpart destroy -F da0
Backup and Restore
Create a backup of the partition table from da0:
/sbin/gpart backup da0 > da0.backup
Restore the partition table from the backup to da0:
/sbin/gpart restore -l da0 < /mnt/da0.backup
Clone the partition table from ada0 to ada1 and ada2:
/sbin/gpart backup ada0 | /sbin/gpart restore -F ada1 ada2
DIAGNOSTICS
gpart: arg0 '%s': Invalid argument The provided geom argument is not a
GEOM provider. Not every device in devfs(4) is a GEOM provider. For
example, a zfs(4) zvol will show up as a GEOM provider only if its
volmode is set properly (refer to zfsprops(7) for details).
SEE ALSO
geom(4), xo_options(7), boot0cfg(8), geom(8), glabel(8), gptboot(8)
HISTORY
The gpart utility appeared in FreeBSD 7.0.
AUTHORS
Marcel Moolenaar <marcel@FreeBSD.org>
CAVEATS
Partition type apple-zfs (6a898cc3-1dd2-11b2-99a6-080020736631) is also
being used on illumos/Solaris platforms for ZFS volumes.
FreeBSD 15.1-STABLE-HBSD May 12, 2026 GPART(8)