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GPART(8)			   BSD 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 [-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 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
	       begins on the logical block address given by the -b start option.  Its size is
	       given by the -s size option.  SI unit suffixes are allowed.  One or both -b and -s
	       options can be omitted.	If so they are automatically calculated.  The type of the
	       partition is given by the -t type option.  Partition types are discussed below in
	       the section entitled PARTITION TYPES.

	       Additional options include:

	       -a alignment  If specified, then gpart utility tries to align start offset and
			     partition size to be multiple of alignment value.

	       -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.

	       -f flags      Additional operational flags.  See the section entitled OPERATIONAL
			     FLAGS below for a discussion about its use.

     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).	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 -b bootcode option specifies a file that contains the
	       bootstrap code.	The contents and size of the file are determined by the parti-
	       tioning scheme.	The -p partcode option specifies a file that contains the boot-
	       strap code intended to be written to a partition.  The partition is specified by
	       the -i index option.  The size of the file must be smaller than the size of the
	       partition.

	       Additional options include:

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     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 -s scheme
	       option determines the scheme to use.  The kernel must have support for a particu-
	       lar scheme before that scheme can be used to partition a disk.

	       Additional options include:

	       -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.

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     delete    Delete a partition from geom geom and further identified by the -i index option.
	       The partition cannot be actively used by the kernel.

	       Additional options include:

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     destroy   Destroy the partitioning scheme as implemented by geom geom.

	       Additional options include:

	       -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.  To change the type
	       of a partition, specify the new type with the -t type option.  To change the label
	       of a partition, specify the new label with the -l label option.	Not all parti-
	       tioning schemes support labels and it is invalid to try to change a partition
	       label in such cases.

	       Additional options include:

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     recover   Recover a corrupt partition's scheme metadata on the geom geom.	See the section
	       entitled RECOVERING below for the additional information.

	       Additional options include:

	       -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.
	       New partition size is expressed in logical block numbers and can be given by the
	       -s size option.	If -s option is omitted then new size is automatically calculated
	       to maximum available from given geom geom.

	       Additional options include:

	       -a alignment  If specified, then gpart utility tries to align partition size to be
			     multiple of alignment value.

	       -f flags      Additional operational flags.  See the section entitled OPERATIONAL
			     FLAGS below for a discussion about its use.

     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.

	       Additional options include:

	       -F	   Destroy partition table on the given provider before doing restore.

	       -l	   Restore partition labels for partitioning schemes that support them.

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     set       Set the named attribute on the partition entry.	See the section entitled
	       ATTRIBUTES below for a list of available attributes.

	       Additional options include:

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     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.	Additional options include:

	       -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.

	       Additional options include:

	       -f flags    Additional operational flags.  See the section entitled OPERATIONAL
			   FLAGS below for a discussion about its use.

     list      See geom(8).

     status    See geom(8).

     load      See geom(8).

     unload    See geom(8).

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, 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 DragonFlyBSD 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 replac-
	    ing 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 pre-
	    vents any type of actions on such partitions.

     PC98   An MBR variant for NEC PC-98 and compatible computers.  Requires the GEOM_PART_PC98
	    kernel option.

     VTOC8  Sun's SMI Volume Table Of Contents, used by SPARC64 and UltraSPARC computers.
	    Requires the GEOM_PART_VTOC8 kernel option.

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 partition-
			    ing schemes.  The scheme-specific type is
			    "!21686148-6449-6E6F-744E-656564454649".

     efi		    The system partition for computers that use the Extensible Firmware
			    Interface (EFI).  In such cases, the GPT partitioning scheme is used
			    and the actual partition type for the system partition can also be
			    specified as "!c12a7328-f81f-11d2-ba4b-00a0c93ec93b".

     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,
			    "!516e7cb5-6ecf-11d6-8ff8-00022d09712b" for GPT, and tag 0x0901 for
			    VTOC8.

     freebsd-ufs	    A FreeBSD partition that contains a UFS or UFS2 filesystem.  The
			    scheme-specific types are "!FreeBSD-UFS" for APM,
			    "!516e7cb6-6ecf-11d6-8ff8-00022d09712b" for GPT, and tag 0x0902 for
			    VTOC8.

     freebsd-vinum	    A FreeBSD partition that contains a Vinum volume.  The scheme-spe-
			    cific types are "!FreeBSD-Vinum" for APM,
			    "!516e7cb8-6ecf-11d6-8ff8-00022d09712b" for GPT, and tag 0x0903 for
			    VTOC8.

     freebsd-zfs	    A FreeBSD partition that contains a ZFS volume.  The scheme-specific
			    types are "!FreeBSD-ZFS" for APM,
			    "!516e7cba-6ecf-11d6-8ff8-00022d09712b" for GPT, and 0x0904 for
			    VTOC8.

     Another symbolic names that can be used with gpart utility are:

     apple-hfs		    An Apple Mac OS X partition that contains a HFS or HFS+ filesystem.
			    The scheme-specific types are "!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 "!Apple_UNIX_SVR2" for APM and
			    "!55465300-0000-11aa-aa11-00306543ecac" for GPT.

     dragonfly-label32	    A DragonFlyBSD partition subdivided into filesystems with a BSD
			    disklabel.	The scheme-specific type is
			    "!9d087404-1ca5-11dc-8817-01301bb8a9f5" for GPT.

     dragonfly-label64	    A DragonFlyBSD partition subdivided into filesystems with a diskla-
			    bel64.  The scheme-specific type is
			    "!3d48ce54-1d16-11dc-8696-01301bb8a9f5" for GPT.

     dragonfly-legacy	    A legacy partition type used in DragonFlyBSD.  The scheme-specific
			    type is "!bd215ab2-1d16-11dc-8696-01301bb8a9f5" for GPT.

     dragonfly-ccd	    A DragonFlyBSD partition used with Concatenated Disk driver.  The
			    scheme-specific type is "!dbd5211b-1ca5-11dc-8817-01301bb8a9f5" for
			    GPT.

     dragonfly-hammer	    A DragonFlyBSD partition that contains a Hammer filesystem.  The
			    scheme-specific type is "!61dc63ac-6e38-11dc-8513-01301bb8a9f5" for
			    GPT.

     dragonfly-hammer2	    A DragonFlyBSD partition that contains a Hammer2 filesystem.  The
			    scheme-specific type is "!5cbb9ad1-862d-11dc-a94d-01301bb8a9f5" for
			    GPT.

     dragonfly-swap	    A DragonFlyBSD partition dedicated to swap space.  The scheme-spe-
			    cific type is "!9d58fdbd-1ca5-11dc-8817-01301bb8a9f5" for GPT.

     dragonfly-ufs	    A DragonFlyBSD partition that contains an UFS1 filesystem.	The
			    scheme-specific type is "!9d94ce7c-1ca5-11dc-8817-01301bb8a9f5" for
			    GPT.

     dragonfly-vinum	    A DragonFlyBSD 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-spe-
			    cific 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.

     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.  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-spe-
			    cific type is "!49f48d5a-b10e-11dc-b99b-0019d1879648" for GPT.

     netbsd-lfs 	    A NetBSD partition that contains an LFS filesystem.  The scheme-spe-
			    cific 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 Pow-
			    erPC systems, notably those made by IBM.  The scheme-specific types
			    are "!65" for MBR and "!0x9e1a2d38-c612-4316-aa26-8b49521e5a8b" 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.

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.

     The scheme-specific attributes for MBR:

     active

     The scheme-specific attributes for PC98:

     active

     bootable

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 parti-
     tioning scheme's metadata, while the second type is located on a specific partition.  Embed-
     ding 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 parti-
     tioning scheme metadata without causing any damage.

     The Master Boot Record (MBR) uses a 512-byte bootstrap code image, embedded into the parti-
     tion 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 KB 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 pro-
     tective 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 KB.  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 par-
     titions, trying to detect ZFS pools.  After all pools are detected, /boot/zfsloader is
     started from the first one found.

     The VTOC8 scheme does not support embedding bootstrap code.  Instead, the 8 KBytes bootstrap
     code image /boot/boot1 should be written with the gpart bootcode command with the -p
     bootcode option to all sufficiently large VTOC8 partitions.  To do this the -i index option
     could be omitted.

     The APM scheme also does not support embedding bootstrap code.  Instead, the 800 KBytes
     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 KB 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 the first sector of a provider is corrupt, the kernel can not detect GPT even if the par-
     tition table itself is not corrupt.  The protective MBR can be rewritten using the dd(1)
     command, to restore the ability to detect the GPT.  The copy of the protective MBR is usu-
     ally located in the /boot/pmbr file.

     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 dan-
     gerous 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.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.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-speci-
	     fied offset and size for alignment with the CHS geometry.	Otherwise the values will
	     be left unchanged.

EXIT STATUS
     Exit status is 0 on success, and 1 if the command fails.

EXAMPLES
     Create a GPT scheme on ada0:

	   /sbin/gpart create -s GPT ada0

     Embed GPT bootstrap code into a protective MBR:

	   /sbin/gpart bootcode -b /boot/pmbr ada0

     Create a dedicated freebsd-boot partition that can boot FreeBSD from a freebsd-ufs parti-
     tion, and install bootstrap code into it.	This partition must be larger than the bootstrap
     code (usually either /boot/gptboot or /boot/gptzfsboot), but smaller than 545 kB since the
     first-stage loader will load the entire partition into memory during boot, regardless of how
     much data it actually contains.  This example uses 88 blocks (44 kB) so the next partition
     will be aligned on a 64 kB boundary without the need to specify an explicit offset or align-
     ment.  The boot partition itself is aligned on a 4 kB boundary.

	   /sbin/gpart add -b 40 -s 88 -t freebsd-boot ada0
	   /sbin/gpart bootcode -p /boot/gptboot -i 1 ada0

     Create a 512MB-sized freebsd-ufs partition to contain a UFS filesystem from which the system
     can boot.

	   /sbin/gpart add -s 512M -t freebsd-ufs ada0

     Create an MBR scheme on ada0, then create a 30GB-sized FreeBSD slice, mark it active and
     install the boot0 boot manager:

	   /sbin/gpart create -s MBR ada0
	   /sbin/gpart add -t freebsd -s 30G ada0
	   /sbin/gpart set -a active -i 1 ada0
	   /sbin/gpart bootcode -b /boot/boot0 ada0

     Now create a BSD scheme (BSD label) with space for up to 20 partitions:

	   /sbin/gpart create -s BSD -n 20 ada0s1

     Create a 1GB-sized UFS partition and a 4GB-sized swap partition:

	   /sbin/gpart add -t freebsd-ufs -s 1G ada0s1
	   /sbin/gpart add -t freebsd-swap -s 4G ada0s1

     Install bootstrap code for the BSD label:

	   /sbin/gpart bootcode -b /boot/boot ada0s1

     Create a VTOC8 scheme on da0:

	   /sbin/gpart create -s VTOC8 da0

     Create a 512MB-sized freebsd-ufs partition to contain a UFS filesystem from which the system
     can boot.

	   /sbin/gpart add -s 512M -t freebsd-ufs da0

     Create a 15GB-sized freebsd-ufs partition to contain a UFS filesystem and aligned on 4KB
     boundaries:

	   /sbin/gpart add -s 15G -t freebsd-ufs -a 4k da0

     After creating all required partitions, embed bootstrap code into them:

	   /sbin/gpart bootcode -p /boot/boot1 da0

     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

SEE ALSO
     dd(1), geom(4), boot0cfg(8), geom(8), gptboot(8)

HISTORY
     The gpart utility appeared in FreeBSD 7.0.

AUTHORS
     Marcel Moolenaar <marcel@FreeBSD.org>

BSD					 August 12, 2014				      BSD
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