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32 .Nd "control utility for the disk partitioning GEOM class"
49 .\" ==== BOOTCODE ====
54 .Op Fl p Ar partcode Fl i Ar index
101 .\" ==== RESTORE ====
144 utility is used to partition GEOM providers, normally disks.
145 The first argument is the action to be taken:
146 .Bl -tag -width ".Cm bootcode"
149 Add a new partition to the partitioning scheme given by
151 The partition type must be specified with
153 The partition's location, size, and other attributes will be calculated
154 automatically if the corresponding options are not specified.
158 command accepts these options:
160 .It Fl a Ar alignment
161 If specified, then the
163 utility tries to align
171 The logical block address where the partition will begin.
172 A SI unit suffix is allowed.
174 Additional operational flags.
175 See the section entitled
176 .Sx "OPERATIONAL FLAGS"
177 below for a discussion
180 The index in the partition table at which the new partition is to be
182 The index determines the name of the device special file used
183 to represent the partition.
185 The label attached to the partition.
186 This option is only valid when used on partitioning schemes that support
189 Create a partition of size
191 A SI unit suffix is allowed.
193 Create a partition of type
195 Partition types are discussed below in the section entitled
196 .Sx "PARTITION TYPES" .
200 Dump a partition table to standard output in a special format used by the
203 .\" ==== BOOTCODE ====
205 Embed bootstrap code into the partitioning scheme's metadata on the
209 or write bootstrap code into a partition (using
216 command accepts these options:
219 Don't preserve the Volume Serial Number for MBR.
220 MBR bootcode contains Volume Serial Number by default, and
222 tries to preserve it when installing new bootstrap code.
223 This option allows to skip the preservation to help with some versions of
225 that don't support Volume Serial Number.
227 Embed bootstrap code from the file
229 into the partitioning scheme's metadata for
231 Not all partitioning schemes have embedded bootstrap code, so the
233 option is scheme-specific in nature (see the section entitled
238 file must match the partitioning scheme's requirements for file content
241 Additional operational flags.
242 See the section entitled
243 .Sx "OPERATIONAL FLAGS"
244 below for a discussion
247 Specify the target partition for
250 Write the bootstrap code from the file
254 partition specified by
256 The size of the file must be smaller than the size of the partition.
260 Commit any pending changes for geom
262 All actions are committed by default and will not result in
264 Actions can be modified with the
266 option so that they are not committed, but become pending.
267 Pending changes are reflected by the geom and the
269 utility, but they are not actually written to disk.
272 action will write all pending changes to disk.
275 Create a new partitioning scheme on a provider given by
277 The scheme to use must be specified with the
283 command accepts these options:
286 Additional operational flags.
287 See the section entitled
288 .Sx "OPERATIONAL FLAGS"
289 below for a discussion
292 The number of entries in the partition table.
293 Every partitioning scheme has a minimum and maximum number of entries.
294 This option allows tables to be created with a number of entries
295 that is within the limits.
296 Some schemes have a maximum equal to the minimum and some schemes have
297 a maximum large enough to be considered unlimited.
298 By default, partition tables are created with the minimum number of
301 Specify the partitioning scheme to use.
302 The kernel must have support for a particular scheme before
303 that scheme can be used to partition a disk.
307 Delete a partition from geom
309 and further identified by the
312 The partition cannot be actively used by the kernel.
316 command accepts these options:
319 Additional operational flags.
320 See the section entitled
321 .Sx "OPERATIONAL FLAGS"
322 below for a discussion
325 Specifies the index of the partition to be deleted.
327 .\" ==== DESTROY ====
329 Destroy the partitioning scheme as implemented by geom
334 command accepts these options:
337 Forced destroying of the partition table even if it is not empty.
339 Additional operational flags.
340 See the section entitled
341 .Sx "OPERATIONAL FLAGS"
342 below for a discussion
347 Modify a partition from geom
349 and further identified by the
352 Only the type and/or label of the partition can be modified.
353 Not all partitioning schemes support labels and it is invalid to
354 try to change a partition label in such cases.
358 command accepts these options:
361 Additional operational flags.
362 See the section entitled
363 .Sx "OPERATIONAL FLAGS"
364 below for a discussion
367 Specifies the index of the partition to be modified.
369 Change the partition label to
372 Change the partition type to
375 .\" ==== RECOVER ====
377 Recover a corrupt partition's scheme metadata on the geom
379 See the section entitled
381 below for the additional information.
385 command accepts these options:
388 Additional operational flags.
389 See the section entitled
390 .Sx "OPERATIONAL FLAGS"
391 below for a discussion
396 Resize a partition from geom
398 and further identified by the
401 If the new size is not specified it is automatically calculated
402 to be the maximum available from
407 command accepts these options:
409 .It Fl a Ar alignment
410 If specified, then the
412 utility tries to align partition
414 to be a multiple of the
418 Additional operational flags.
419 See the section entitled
420 .Sx "OPERATIONAL FLAGS"
421 below for a discussion
424 Specifies the index of the partition to be resized.
426 Specifies the new size of the partition, in logical blocks.
427 A SI unit suffix is allowed.
429 .\" ==== RESTORE ====
431 Restore the partition table from a backup previously created by the
433 action and read from standard input.
434 Only the partition table is restored.
435 This action does not affect the content of partitions.
436 After restoring the partition table and writing bootcode if needed,
437 user data must be restored from backup.
441 command accepts these options:
444 Destroy partition table on the given
446 before doing restore.
448 Additional operational flags.
449 See the section entitled
450 .Sx "OPERATIONAL FLAGS"
451 below for a discussion
454 Restore partition labels for partitioning schemes that support them.
458 Set the named attribute on the partition entry.
459 See the section entitled
461 below for a list of available attributes.
465 command accepts these options:
468 Specifies the attribute to set.
470 Additional operational flags.
471 See the section entitled
472 .Sx "OPERATIONAL FLAGS"
473 below for a discussion
476 Specifies the index of the partition on which the attribute will be set.
480 Show current partition information for the specified geoms, or all
481 geoms if none are specified.
482 The default output includes the logical starting block of each
483 partition, the partition size in blocks, the partition index number,
484 the partition type, and a human readable partition size.
485 Block sizes and locations are based on the device's Sectorsize
491 command accepts these options:
494 For partitioning schemes that support partition labels, print them
495 instead of partition type.
497 Show provider names instead of partition indexes.
499 Show raw partition type instead of symbolic name.
503 Revert any pending changes for geom
505 This action is the opposite of the
507 action and can be used to undo any changes that have not been committed.
510 Clear the named attribute on the partition entry.
511 See the section entitled
513 below for a list of available attributes.
517 command accepts these options:
520 Specifies the attribute to clear.
522 Additional operational flags.
523 See the section entitled
524 .Sx "OPERATIONAL FLAGS"
525 below for a discussion
528 Specifies the index of the partition on which the attribute will be cleared.
543 .Sh PARTITIONING SCHEMES
544 Several partitioning schemes are supported by the
547 .Bl -tag -width ".Cm VTOC8"
549 Apple Partition Map, used by PowerPC(R) Macintosh(R) computers.
554 Traditional BSD disklabel, usually used to subdivide MBR partitions.
556 This scheme can also be used as the sole partitioning method, without
558 Partition editing tools from other operating systems often do not
559 understand the bare disklabel partition layout, so this is sometimes
561 .Dq dangerously dedicated .
567 64-bit implementation of BSD disklabel used in DragonFlyBSD to subdivide MBR
573 The Logical Disk Manager is an implementation of volume manager for
574 Microsoft Windows NT.
579 GUID Partition Table is used on Intel-based Macintosh computers and
580 gradually replacing MBR on most PCs and other systems.
585 Master Boot Record is used on PCs and removable media.
591 option adds support for the Extended Boot Record (EBR),
592 which is used to define a logical partition.
594 .Cm GEOM_PART_EBR_COMPAT
595 option enables backward compatibility for partition names
597 It also prevents any type of actions on such partitions.
599 Sun's SMI Volume Table Of Contents, used by
609 Partition types are identified on disk by particular strings or magic
613 utility uses symbolic names for common partition types so the user
614 does not need to know these values or other details of the partitioning
618 utility also allows the user to specify scheme-specific partition types
619 for partition types that do not have symbolic names.
620 Symbolic names currently understood and used by
623 .Bl -tag -width ".Cm dragonfly-disklabel64"
625 The system partition dedicated to storing boot loaders on some Apple
627 The scheme-specific types are
630 .Qq Li "!Apple_Bootstrap"
632 .Qq Li "!426f6f74-0000-11aa-aa11-00306543ecac"
635 The system partition dedicated to second stage of the boot loader program.
636 Usually it is used by the GRUB 2 loader for GPT partitioning schemes.
637 The scheme-specific type is
638 .Qq Li "!21686148-6449-6E6F-744E-656564454649" .
640 The system partition for computers that use the Extensible Firmware
642 The scheme-specific types are
645 .Qq Li "!c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
650 partition subdivided into filesystems with a
653 This is a legacy partition type and should not be used for the APM
655 The scheme-specific types are
660 .Qq Li "!516e7cb4-6ecf-11d6-8ff8-00022d09712b"
665 partition dedicated to bootstrap code.
666 The scheme-specific type is
667 .Qq Li "!83bd6b9d-7f41-11dc-be0b-001560b84f0f"
672 partition dedicated to swap space.
673 The scheme-specific types are
674 .Qq Li "!FreeBSD-swap"
676 .Qq Li "!516e7cb5-6ecf-11d6-8ff8-00022d09712b"
677 for GPT, and tag 0x0901 for VTOC8.
681 partition that contains a UFS or UFS2 filesystem.
682 The scheme-specific types are
683 .Qq Li "!FreeBSD-UFS"
685 .Qq Li "!516e7cb6-6ecf-11d6-8ff8-00022d09712b"
686 for GPT, and tag 0x0902 for VTOC8.
690 partition that contains a Vinum volume.
691 The scheme-specific types are
692 .Qq Li "!FreeBSD-Vinum"
694 .Qq Li "!516e7cb8-6ecf-11d6-8ff8-00022d09712b"
695 for GPT, and tag 0x0903 for VTOC8.
699 partition that contains a ZFS volume.
700 The scheme-specific types are
701 .Qq Li "!FreeBSD-ZFS"
703 .Qq Li "!516e7cba-6ecf-11d6-8ff8-00022d09712b"
704 for GPT, and 0x0904 for VTOC8.
707 Other symbolic names that can be used with the
710 .Bl -tag -width ".Cm dragonfly-disklabel64"
712 An Apple macOS partition used for the Apple file system, APFS.
713 .It Cm apple-core-storage
714 An Apple Mac OS X partition used by logical volume manager known as
716 The scheme-specific type is
717 .Qq Li "!53746f72-6167-11aa-aa11-00306543ecac"
720 An Apple Mac OS X partition that contains a HFS or HFS+ filesystem.
721 The scheme-specific types are
726 .Qq Li "!48465300-0000-11aa-aa11-00306543ecac"
729 An Apple Mac OS X partition dedicated to partition metadata that descibes
731 The scheme-specific type is
732 .Qq Li "!4c616265-6c00-11aa-aa11-00306543ecac"
735 An Apple Mac OS X partition used in a software RAID configuration.
736 The scheme-specific type is
737 .Qq Li "!52414944-0000-11aa-aa11-00306543ecac"
739 .It Cm apple-raid-offline
740 An Apple Mac OS X partition used in a software RAID configuration.
741 The scheme-specific type is
742 .Qq Li "!52414944-5f4f-11aa-aa11-00306543ecac"
744 .It Cm apple-tv-recovery
745 An Apple Mac OS X partition used by Apple TV.
746 The scheme-specific type is
747 .Qq Li "!5265636f-7665-11aa-aa11-00306543ecac"
750 An Apple Mac OS X partition that contains a UFS filesystem.
751 The scheme-specific types are
754 .Qq Li "!Apple_UNIX_SVR2"
756 .Qq Li "!55465300-0000-11aa-aa11-00306543ecac"
759 An Apple Mac OS X partition that contains a ZFS volume.
760 The scheme-specific type is
761 .Qq Li "!6a898cc3-1dd2-11b2-99a6-080020736631"
762 for GPT. The same GUID is being used also for
763 .Sy illumos/Solaris /usr partition .
767 .It Cm dragonfly-label32
768 A DragonFlyBSD partition subdivided into filesystems with a
771 The scheme-specific type is
772 .Qq Li "!9d087404-1ca5-11dc-8817-01301bb8a9f5"
774 .It Cm dragonfly-label64
775 A DragonFlyBSD partition subdivided into filesystems with a
777 The scheme-specific type is
778 .Qq Li "!3d48ce54-1d16-11dc-8696-01301bb8a9f5"
780 .It Cm dragonfly-legacy
781 A legacy partition type used in DragonFlyBSD.
782 The scheme-specific type is
783 .Qq Li "!bd215ab2-1d16-11dc-8696-01301bb8a9f5"
786 A DragonFlyBSD partition used with Concatenated Disk driver.
787 The scheme-specific type is
788 .Qq Li "!dbd5211b-1ca5-11dc-8817-01301bb8a9f5"
790 .It Cm dragonfly-hammer
791 A DragonFlyBSD partition that contains a Hammer filesystem.
792 The scheme-specific type is
793 .Qq Li "!61dc63ac-6e38-11dc-8513-01301bb8a9f5"
795 .It Cm dragonfly-hammer2
796 A DragonFlyBSD partition that contains a Hammer2 filesystem.
797 The scheme-specific type is
798 .Qq Li "!5cbb9ad1-862d-11dc-a94d-01301bb8a9f5"
800 .It Cm dragonfly-swap
801 A DragonFlyBSD partition dedicated to swap space.
802 The scheme-specific type is
803 .Qq Li "!9d58fdbd-1ca5-11dc-8817-01301bb8a9f5"
806 A DragonFlyBSD partition that contains an UFS1 filesystem.
807 The scheme-specific type is
808 .Qq Li "!9d94ce7c-1ca5-11dc-8817-01301bb8a9f5"
810 .It Cm dragonfly-vinum
811 A DragonFlyBSD partition used with Logical Volume Manager.
812 The scheme-specific type is
813 .Qq Li "!9dd4478f-1ca5-11dc-8817-01301bb8a9f5"
816 A partition subdivided into filesystems with a EBR.
817 The scheme-specific type is
821 A partition that contains a FAT16 filesystem.
822 The scheme-specific type is
826 A partition that contains a FAT32 filesystem.
827 The scheme-specific type is
831 A partition that contains a FAT32 (LBA) filesystem.
832 The scheme-specific type is
836 A Linux partition that contains some filesystem with data.
837 The scheme-specific types are
840 .Qq Li "!0fc63daf-8483-4772-8e79-3d69d8477de4"
843 A Linux partition dedicated to Logical Volume Manager.
844 The scheme-specific types are
847 .Qq Li "!e6d6d379-f507-44c2-a23c-238f2a3df928"
850 A Linux partition used in a software RAID configuration.
851 The scheme-specific types are
854 .Qq Li "!a19d880f-05fc-4d3b-a006-743f0f84911e"
857 A Linux partition dedicated to swap space.
858 The scheme-specific types are
861 .Qq Li "!0657fd6d-a4ab-43c4-84e5-0933c84b4f4f"
864 A partition that is sub-partitioned by a Master Boot Record (MBR).
865 This type is known as
866 .Qq Li "!024dee41-33e7-11d3-9d69-0008c781f39f"
869 A basic data partition (BDP) for Microsoft operating systems.
870 In the GPT this type is the equivalent to partition types
875 This type is used for GPT exFAT partitions.
876 The scheme-specific type is
877 .Qq Li "!ebd0a0a2-b9e5-4433-87c0-68b6b72699c7"
880 A partition that contains Logical Disk Manager (LDM) volumes.
881 The scheme-specific types are
884 .Qq Li "!af9b60a0-1431-4f62-bc68-3311714a69ad"
886 .It Cm ms-ldm-metadata
887 A partition that contains Logical Disk Manager (LDM) database.
888 The scheme-specific type is
889 .Qq Li "!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3"
892 A NetBSD partition used with Concatenated Disk driver.
893 The scheme-specific type is
894 .Qq Li "!2db519c4-b10f-11dc-b99b-0019d1879648"
897 An encrypted NetBSD partition.
898 The scheme-specific type is
899 .Qq Li "!2db519ec-b10f-11dc-b99b-0019d1879648"
902 A NetBSD partition that contains an UFS filesystem.
903 The scheme-specific type is
904 .Qq Li "!49f48d5a-b10e-11dc-b99b-0019d1879648"
907 A NetBSD partition that contains an LFS filesystem.
908 The scheme-specific type is
909 .Qq Li "!49f48d82-b10e-11dc-b99b-0019d1879648"
912 A NetBSD partition used in a software RAID configuration.
913 The scheme-specific type is
914 .Qq Li "!49f48daa-b10e-11dc-b99b-0019d1879648"
917 A NetBSD partition dedicated to swap space.
918 The scheme-specific type is
919 .Qq Li "!49f48d32-b10e-11dc-b99b-0019d1879648"
922 A partition that contains a NTFS or exFAT filesystem.
923 The scheme-specific type is
927 The system partition dedicated to storing boot loaders on some PowerPC systems,
928 notably those made by IBM.
929 The scheme-specific types are
932 .Qq Li "!9e1a2d38-c612-4316-aa26-8b49521e5a8b"
935 A illumos/Solaris partition dedicated to boot loader.
936 The scheme-specific type is
937 .Qq Li "!6a82cb45-1dd2-11b2-99a6-080020736631"
940 A illumos/Solaris partition dedicated to root filesystem.
941 The scheme-specific type is
942 .Qq Li "!6a85cf4d-1dd2-11b2-99a6-080020736631"
945 A illumos/Solaris partition dedicated to swap.
946 The scheme-specific type is
947 .Qq Li "!6a87c46f-1dd2-11b2-99a6-080020736631"
949 .It Cm solaris-backup
950 A illumos/Solaris partition dedicated to backup.
951 The scheme-specific type is
952 .Qq Li "!6a8b642b-1dd2-11b2-99a6-080020736631"
955 A illumos/Solaris partition dedicated to /var filesystem.
956 The scheme-specific type is
957 .Qq Li "!6a8ef2e9-1dd2-11b2-99a6-080020736631"
960 A illumos/Solaris partition dedicated to /home filesystem.
961 The scheme-specific type is
962 .Qq Li "!6a90ba39-1dd2-11b2-99a6-080020736631"
964 .It Cm solaris-altsec
965 A illumos/Solaris partition dedicated to alternate sector.
966 The scheme-specific type is
967 .Qq Li "!6a9283a5-1dd2-11b2-99a6-080020736631"
969 .It Cm solaris-reserved
970 A illumos/Solaris partition dedicated to reserved space.
971 The scheme-specific type is
972 .Qq Li "!6a945a3b-1dd2-11b2-99a6-080020736631"
975 A partition that contains a VMware File System (VMFS).
976 The scheme-specific types are
979 .Qq Li "!aa31e02a-400f-11db-9590-000c2911d1b8"
981 .It Cm vmware-vmkdiag
982 A partition that contains a VMware diagostic filesystem.
983 The scheme-specific types are
986 .Qq Li "!9d275380-40ad-11db-bf97-000c2911d1b8"
988 .It Cm vmware-reserved
989 A VMware reserved partition.
990 The scheme-specific type is
991 .Qq Li "!9198effc-31c0-11db-8f-78-000c2911d1b8"
993 .It Cm vmware-vsanhdr
994 A partition claimed by VMware VSAN.
995 The scheme-specific type is
996 .Qq Li "!381cfccc-7288-11e0-92ee-000c2911d0b2"
1000 The scheme-specific attributes for EBR:
1001 .Bl -tag -width ".Cm active"
1005 The scheme-specific attributes for GPT:
1006 .Bl -tag -width ".Cm bootfailed"
1010 stage 1 boot loader will try to boot the system from this partition.
1011 Multiple partitions can be marked with the
1018 Setting this attribute automatically sets the
1023 stage 1 boot loader will try to boot the system from this partition only once.
1024 Multiple partitions can be marked with the
1033 This attribute should not be manually managed.
1034 It is managed by the
1036 stage 1 boot loader and the
1037 .Pa /etc/rc.d/gptboot
1043 Setting this attribute overwrites the Protective MBR with a new one where
1044 the 0xee partition is the second, rather than the first record.
1045 This resolves a BIOS compatibility issue with some Lenovo models including the
1046 X220, T420, and T520, allowing them to boot from GPT partitioned disks
1050 The scheme-specific attributes for MBR:
1051 .Bl -tag -width ".Cm active"
1056 supports several partitioning schemes and each scheme uses different
1058 The bootstrap code is located in a specific disk area for each partitioning
1059 scheme, and may vary in size for different schemes.
1061 Bootstrap code can be separated into two types.
1062 The first type is embedded in the partitioning scheme's metadata, while the
1063 second type is located on a specific partition.
1064 Embedding bootstrap code should only be done with the
1069 The GEOM PART class knows how to safely embed bootstrap code into
1070 specific partitioning scheme metadata without causing any damage.
1072 The Master Boot Record (MBR) uses a 512-byte bootstrap code image, embedded
1073 into the partition table's metadata area.
1074 There are two variants of this bootstrap code:
1079 searches for a partition with the
1083 section) in the partition table.
1084 Then it runs next bootstrap stage.
1087 image contains a boot manager with some additional interactive functions
1088 for multi-booting from a user-selected partition.
1090 A BSD disklabel is usually created inside an MBR partition (slice)
1094 .Sx "PARTITION TYPES"
1096 It uses 8 KB size bootstrap code image
1098 embedded into the partition table's metadata area.
1100 Both types of bootstrap code are used to boot from the GUID Partition Table.
1101 First, a protective MBR is embedded into the first disk sector from the
1104 It searches through the GPT for a
1107 .Sx "PARTITION TYPES"
1108 section) and runs the next bootstrap stage from it.
1111 partition should be smaller than 545 KB.
1112 It can be located either before or after other
1114 partitions on the disk.
1115 There are two variants of bootstrap code to write to this partition:
1118 .Pa /boot/gptzfsboot .
1121 is used to boot from UFS partitions.
1125 partitions in the GPT and selects one to boot based on the
1130 If neither attribute is found,
1132 boots from the first
1136 .Pq the third bootstrap stage
1137 is loaded from the first partition that matches these conditions.
1140 for more information.
1142 .Pa /boot/gptzfsboot
1143 is used to boot from ZFS.
1144 It searches through the GPT for
1146 partitions, trying to detect ZFS pools.
1147 After all pools are detected,
1149 is started from the first one found set as bootable.
1151 The VTOC8 scheme does not support embedding bootstrap code.
1152 Instead, the 8 KBytes bootstrap code image
1154 should be written with the
1158 option to all sufficiently large VTOC8 partitions.
1161 option could be omitted.
1163 The APM scheme also does not support embedding bootstrap code.
1164 Instead, the 800 KBytes bootstrap code image
1166 should be written with the
1168 command to a partition of type
1170 which should also be 800 KB in size.
1171 .Sh OPERATIONAL FLAGS
1172 Actions other than the
1176 actions take an optional
1179 This option is used to specify action-specific operational flags.
1184 flag so that the action is immediately
1186 The user can specify
1188 to have the action result in a pending change that can later, with
1189 other pending changes, be committed as a single compound change with
1192 action or reverted with the
1196 The GEOM PART class supports recovering of partition tables only for GPT.
1197 The GPT primary metadata is stored at the beginning of the device.
1198 For redundancy, a secondary
1200 copy of the metadata is stored at the end of the device.
1201 As a result of having two copies, some corruption of metadata is not
1202 fatal to the working of GPT.
1203 When the kernel detects corrupt metadata, it marks this table as corrupt
1204 and reports the problem.
1208 are the only operations allowed on corrupt tables.
1210 If one GPT header appears to be corrupt but the other copy remains intact,
1211 the kernel will log the following:
1212 .Bd -literal -offset indent
1213 GEOM: provider: the primary GPT table is corrupt or invalid.
1214 GEOM: provider: using the secondary instead -- recovery strongly advised.
1218 .Bd -literal -offset indent
1219 GEOM: provider: the secondary GPT table is corrupt or invalid.
1220 GEOM: provider: using the primary only -- recovery suggested.
1229 will report about corrupt tables.
1231 If the size of the device has changed (e.g.,\& volume expansion) the
1232 secondary GPT header will no longer be located in the last sector.
1233 This is not a metadata corruption, but it is dangerous because any
1234 corruption of the primary GPT will lead to loss of the partition table.
1235 This problem is reported by the kernel with the message:
1236 .Bd -literal -offset indent
1237 GEOM: provider: the secondary GPT header is not in the last LBA.
1240 This situation can be recovered with the
1243 This command reconstructs the corrupt metadata using known valid
1244 metadata and relocates the secondary GPT to the end of the device.
1247 The GEOM PART class can detect the same partition table visible through
1248 different GEOM providers, and some of them will be marked as corrupt.
1249 Be careful when choosing a provider for recovery.
1250 If you choose incorrectly you can destroy the metadata of another GEOM class,
1251 e.g.,\& GEOM MIRROR or GEOM LABEL.
1252 .Sh SYSCTL VARIABLES
1255 variables can be used to control the behavior of the
1258 The default value is shown next to each variable.
1259 .Bl -tag -width indent
1260 .It Va kern.geom.part.allow_nesting : No 0
1261 By default, some schemes (currently BSD, BSD64 and VTOC8) do not permit
1262 further nested partitioning.
1263 This variable overrides this restriction and allows arbitrary nesting (except
1264 within partitions created at offset 0).
1265 Some schemes have their own separate checks, for which see below.
1266 .It Va kern.geom.part.auto_resize : No 1
1267 This variable controls automatic resize behavior of the
1270 When this variable is enable and new size of provider is detected, the schema
1271 metadata is resized but all changes are not saved to disk, until
1273 is run to confirm changes.
1274 This behavior is also reported with diagnostic message:
1275 .Sy "GEOM_PART: (provider) was automatically resized."
1276 .Sy "Use `gpart commit (provider)` to save changes or `gpart undo (provider)`"
1277 .Sy "to revert them."
1278 .It Va kern.geom.part.check_integrity : No 1
1279 This variable controls the behaviour of metadata integrity checks.
1280 When integrity checks are enabled, the
1282 GEOM class verifies all generic partition parameters obtained from the
1284 If some inconsistency is detected, the partition table will be
1285 rejected with a diagnostic message:
1286 .Sy "GEOM_PART: Integrity check failed (provider, scheme)" .
1287 .It Va kern.geom.part.gpt.allow_nesting : No 0
1288 By default the GPT scheme is allowed only at the outermost nesting level.
1289 This variable allows this restriction to be removed.
1290 .It Va kern.geom.part.ldm.debug : No 0
1291 Debug level of the Logical Disk Manager (LDM) module.
1292 This can be set to a number between 0 and 2 inclusive.
1293 If set to 0 minimal debug information is printed,
1294 and if set to 2 the maximum amount of debug information is printed.
1295 .It Va kern.geom.part.ldm.show_mirrors : No 0
1296 This variable controls how the Logical Disk Manager (LDM) module handles
1298 By default mirrored volumes are shown as partitions with type
1301 .Sx "PARTITION TYPES"
1303 If this variable set to 1 each component of the mirrored volume will be
1304 present as independent partition.
1306 This may break a mirrored volume and lead to data damage.
1307 .It Va kern.geom.part.mbr.enforce_chs : No 0
1308 Specify how the Master Boot Record (MBR) module does alignment.
1309 If this variable is set to a non-zero value, the module will automatically
1310 recalculate the user-specified offset and size for alignment with the CHS
1312 Otherwise the values will be left unchanged.
1313 .It Va kern.geom.part.separator : No ""
1314 Specify an optional separator that will be inserted between the GEOM name
1319 Note that setting this variable may break software which assumes a particular
1323 Exit status is 0 on success, and 1 if the command fails.
1325 The examples below assume that the disk's logical block size is 512
1326 bytes, regardless of its physical block size.
1328 In this example, we will format
1330 with the GPT scheme and create boot, swap and root partitions.
1331 First, we need to create the partition table:
1332 .Bd -literal -offset indent
1333 /sbin/gpart create -s GPT ada0
1336 Next, we install a protective MBR with the first-stage bootstrap code.
1337 The protective MBR lists a single, bootable partition spanning the
1338 entire disk, thus allowing non-GPT-aware BIOSes to boot from the disk
1339 and preventing tools which do not understand the GPT scheme from
1340 considering the disk to be unformatted.
1341 .Bd -literal -offset indent
1342 /sbin/gpart bootcode -b /boot/pmbr ada0
1345 We then create a dedicated
1347 partition to hold the second-stage boot loader, which will load the
1349 kernel and modules from a UFS or ZFS filesystem.
1350 This partition must be larger than the bootstrap code
1355 .Pa /boot/gptzfsboot
1358 but smaller than 545 kB since the first-stage loader will load the
1359 entire partition into memory during boot, regardless of how much data
1360 it actually contains.
1361 We create a 472-block (236 kB) boot partition at offset 40, which is
1362 the size of the partition table (34 blocks or 17 kB) rounded up to the
1363 nearest 4 kB boundary.
1364 .Bd -literal -offset indent
1365 /sbin/gpart add -b 40 -s 472 -t freebsd-boot ada0
1366 /sbin/gpart bootcode -p /boot/gptboot -i 1 ada0
1369 We now create a 4 GB swap partition at the first available offset,
1370 which is 40 + 472 = 512 blocks (256 kB).
1371 .Bd -literal -offset indent
1372 /sbin/gpart add -s 4G -t freebsd-swap ada0
1375 Aligning the swap partition and all subsequent partitions on a 256 kB
1376 boundary ensures optimal performance on a wide range of media, from
1377 plain old disks with 512-byte blocks, through modern
1379 disks with 4096-byte physical blocks, to RAID volumes with stripe
1380 sizes of up to 256 kB.
1382 Finally, we create and format an 8 GB
1384 partition for the root filesystem, leaving the rest of the slice free
1385 for additional filesystems:
1386 .Bd -literal -offset indent
1387 /sbin/gpart add -s 8G -t freebsd-ufs ada0
1388 /sbin/newfs -Uj /dev/ada0p3
1391 In this example, we will format
1393 with the MBR scheme and create a single partition which we subdivide
1398 First, we create the partition table and a single 64 GB partition,
1399 then we mark that partition active (bootable) and install the
1400 first-stage boot loader:
1401 .Bd -literal -offset indent
1402 /sbin/gpart create -s MBR ada0
1403 /sbin/gpart add -t freebsd -s 64G ada0
1404 /sbin/gpart set -a active -i 1 ada0
1405 /sbin/gpart bootcode -b /boot/boot0 ada0
1408 Next, we create a disklabel in that partition
1411 in disklabel terminology
1413 with room for up to 20 partitions:
1414 .Bd -literal -offset indent
1415 /sbin/gpart create -s BSD -n 20 ada0s1
1418 We then create an 8 GB root partition and a 4 GB swap partition:
1419 .Bd -literal -offset indent
1420 /sbin/gpart add -t freebsd-ufs -s 8G ada0s1
1421 /sbin/gpart add -t freebsd-swap -s 4G ada0s1
1424 Finally, we install the appropriate boot loader for the
1427 .Bd -literal -offset indent
1428 /sbin/gpart bootcode -b /boot/boot ada0s1
1432 Create a VTOC8 scheme on
1434 .Bd -literal -offset indent
1435 /sbin/gpart create -s VTOC8 da0
1438 Create a 512MB-sized
1440 partition to contain a UFS filesystem from which the system can boot.
1441 .Bd -literal -offset indent
1442 /sbin/gpart add -s 512M -t freebsd-ufs da0
1447 partition to contain a UFS filesystem and aligned on 4KB boundaries:
1448 .Bd -literal -offset indent
1449 /sbin/gpart add -s 15G -t freebsd-ufs -a 4k da0
1452 After creating all required partitions, embed bootstrap code into them:
1453 .Bd -literal -offset indent
1454 /sbin/gpart bootcode -p /boot/boot1 da0
1456 .Ss Deleting Partitions and Destroying the Partitioning Scheme
1459 error is shown when trying to destroy a partition table, remember that
1460 all of the partitions must be deleted first with the
1465 has three partitions:
1466 .Bd -literal -offset indent
1467 /sbin/gpart delete -i 3 da0
1468 /sbin/gpart delete -i 2 da0
1469 /sbin/gpart delete -i 1 da0
1470 /sbin/gpart destroy da0
1473 Rather than deleting each partition and then destroying the partitioning
1476 option can be given with
1478 to delete all of the partitions before destroying the partitioning scheme.
1479 This is equivalent to the previous example:
1480 .Bd -literal -offset indent
1481 /sbin/gpart destroy -F da0
1483 .Ss Backup and Restore
1485 Create a backup of the partition table from
1487 .Bd -literal -offset indent
1488 /sbin/gpart backup da0 > da0.backup
1491 Restore the partition table from the backup to
1493 .Bd -literal -offset indent
1494 /sbin/gpart restore -l da0 < /mnt/da0.backup
1497 Clone the partition table from
1503 .Bd -literal -offset indent
1504 /sbin/gpart backup ada0 | /sbin/gpart restore -F ada1 ada2
1517 .An Marcel Moolenaar Aq Mt marcel@FreeBSD.org
1521 (6a898cc3-1dd2-11b2-99a6-080020736631) is also being used
1522 on illumos/Solaris platforms for ZFS volumes.