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GPART(8) FreeBSD System Manager's Manual GPART(8)

Содержание

[править] NAME

    gpart — control utility for the disk partitioning GEOM class

[править] SYNOPSIS

    To add support for the disk partitioning GEOM class, place one or more of
    the following lines in the kernel configuration file:
          options GEOM_PART_APM
          options GEOM_PART_BSD
          options GEOM_PART_GPT
          options GEOM_PART_LDM
          options GEOM_PART_MBR
          options GEOM_PART_EBR
          options GEOM_PART_EBR_COMPAT
          options GEOM_PART_PC98
          options GEOM_PART_VTOC8
    These options provide support for the various types of partitioning
    schemes supported by the gpart utility.  See PARTITIONING SCHEMES below
    for more details.
    Usage of the gpart utility:
    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

[править] 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 rep‐
                            resent 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 partition‐
              ing 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 partitioning scheme.  The -p
              partcode option specifies a file that contains the bootstrap
              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 com‐
              mitted 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 particular 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 num‐
                          ber 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 partitioning 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 par‐
              tition table is restored.  This action does not affect the con‐
              tent 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 sec‐
              tion 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 the current partition information of the specified geoms
              or all geoms if none are specified.  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 sec‐
              tion 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.

[править] 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 parti‐
           tions.  (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.
    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.
    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.

[править] 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 are:
    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-spe‐
                     cific type is "!21686148-6449-6E6F-744E-656564454649".
    efi              The system partition for computers that use the Extensi‐
                     ble 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-00a0c93ec93ab".
    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 filesys‐
                     tem.  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-specific 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.
    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-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-specifig type is
                     "!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3" for GPT.

[править] 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 might be
                marked with the bootme attribute.  In such scenario the
                gptboot will try all bootme partitions one by one, until the
                next boot stage is successfully entered.
    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.  Parti‐
                tions with both bootonce and bootme attributes are tried
                before partitions with only the bootme attribute.  Before
                bootonce partition is tried, the gptboot removes the bootme
                attribute and tries to execute the next boot stage.  If it
                fails, the bootonce attribute that is now alone is replaced
                with the bootfailed attribute.  If the execution of the next
                boot stage succeeds, but the system is not fully booted, the
                gptboot will look for bootonce attributes alone (without the
                bootme attribute) on the next system boot and will replace
                those with the bootfailed attribute.  If the system is fully
                booted, the /etc/rc.d/gptboot start-up script will look for
                partition with the bootonce attribute alone, will remove the
                attribute and log that the system was successfully booted
                from this partition.  There should be at most one bootonce
                partition when system is successfully booted.  Multiple par‐
                titions might be marked with the bootonce and bootme
                attribute pairs.
    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.  This attribute is used to mark partitions
                that had the bootonce attribute set, but we failed to boot
                from them.  Once we successfully boot, the /etc/rc.d/gptboot
                script will log all the partitions we failed to boot from and
                will remove the bootfailed attributes.
    The scheme-specific attributes for MBR:
    active
    The scheme-specific attributes for PC98:
    active
    bootable

[править] BOOTSTRAPPING

    FreeBSD supports several partitioning schemes and each scheme uses dif‐
    ferent 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 embed‐
    ded 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, embed‐
    ded 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 KB size boot‐
    strap 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 Ta‐
    ble.  First, a protective MBR is embedded into the first disk sector from
    the /boot/pmbr image.  It searches the GPT freebsd-boot partition (see
    the PARTITION TYPES section) in the GPT and runs the next bootstrap stage
    from it.  The freebsd-boot partition should be smaller than 545 KB.
    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.  It searches freebsd-ufs GPT partitions and starts /boot/loader (the
    third bootstrap stage) if found.  The /boot/gptzfsboot is used to boot
    from ZFS.  It searches freebsd-zfs GPT partitions and starts
    /boot/zfsloader if 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 freebsd-boot,
    which should also be 800 KB in size.

[править] 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.

[править] 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 partition 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 usually 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 cor‐
    rupt tables.
    If the size of the device has changed (e.g. volume expansion) the sec‐
    ondary 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 relo‐
    cates 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 cor‐
    rupt.  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.

[править] 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 mini‐
            mal 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 sec‐
            tion).  If this variable set to 1 each component of the mirrored
            volume will be present as independet partition.  NOTE: This may
            break a mirrored volume and lead to data damage.

[править] EXIT STATUS

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

[править] EXAMPLES

    Create a GPT scheme on ad0:
          /sbin/gpart create -s GPT ad0
    Embed GPT bootstrap code into a protective MBR:
          /sbin/gpart bootcode -b /boot/pmbr ad0
    Create a dedicated freebsd-boot partition that can boot FreeBSD from a
    freebsd-ufs partition, and install bootstrap code into it.  This parti‐
    tion 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 94 blocks (47
    kB) so the next partition will be aligned on a 64 kB boundary without the
    need to specify an explicit offset or alignment.
          /sbin/gpart add -b 34 -s 94 -t freebsd-boot ad0
          /sbin/gpart bootcode -p /boot/gptboot -i 1 ad0
    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 ad0
    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

[править] SEE ALSO

dd(1), geom(4), boot0cfg(8), geom(8)

[править] HISTORY

    The gpart utility appeared in FreeBSD 7.0.

[править] AUTHORS

    Marcel Moolenaar <marcel@FreeBSD.org>

FreeBSD 9.0 March 19, 2012 FreeBSD 9.0

Источник — «http://xgu.ru/wiki/man/orig/gpart»