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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 An 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 An 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 An 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
611 for additional information on labelization of devices and partitions.
613 Partition types are identified on disk by particular strings or magic
617 utility uses symbolic names for common partition types so the user
618 does not need to know these values or other details of the partitioning
622 utility also allows the user to specify scheme-specific partition types
623 for partition types that do not have symbolic names.
624 Symbolic names currently understood and used by
627 .Bl -tag -width ".Cm dragonfly-disklabel64"
629 The system partition dedicated to storing boot loaders on some Apple
631 The scheme-specific types are
634 .Qq Li "!Apple_Bootstrap"
636 .Qq Li "!426f6f74-0000-11aa-aa11-00306543ecac"
639 The system partition dedicated to second stage of the boot loader program.
640 Usually it is used by the GRUB 2 loader for GPT partitioning schemes.
641 The scheme-specific type is
642 .Qq Li "!21686148-6449-6E6F-744E-656564454649" .
644 The system partition for computers that use the Extensible Firmware
646 The scheme-specific types are
649 .Qq Li "!c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
654 partition subdivided into filesystems with a
657 This is a legacy partition type and should not be used for the APM
659 The scheme-specific types are
664 .Qq Li "!516e7cb4-6ecf-11d6-8ff8-00022d09712b"
669 partition dedicated to bootstrap code.
670 The scheme-specific type is
671 .Qq Li "!83bd6b9d-7f41-11dc-be0b-001560b84f0f"
676 partition dedicated to swap space.
677 The scheme-specific types are
678 .Qq Li "!FreeBSD-swap"
680 .Qq Li "!516e7cb5-6ecf-11d6-8ff8-00022d09712b"
681 for GPT, and tag 0x0901 for VTOC8.
685 partition that contains a UFS or UFS2 filesystem.
686 The scheme-specific types are
687 .Qq Li "!FreeBSD-UFS"
689 .Qq Li "!516e7cb6-6ecf-11d6-8ff8-00022d09712b"
690 for GPT, and tag 0x0902 for VTOC8.
694 partition that contains a Vinum volume.
695 The scheme-specific types are
696 .Qq Li "!FreeBSD-Vinum"
698 .Qq Li "!516e7cb8-6ecf-11d6-8ff8-00022d09712b"
699 for GPT, and tag 0x0903 for VTOC8.
703 partition that contains a ZFS volume.
704 The scheme-specific types are
705 .Qq Li "!FreeBSD-ZFS"
707 .Qq Li "!516e7cba-6ecf-11d6-8ff8-00022d09712b"
708 for GPT, and 0x0904 for VTOC8.
711 Other symbolic names that can be used with the
714 .Bl -tag -width ".Cm dragonfly-disklabel64"
716 An Apple macOS partition used for the Apple file system, APFS.
717 .It Cm apple-core-storage
718 An Apple Mac OS X partition used by logical volume manager known as
720 The scheme-specific type is
721 .Qq Li "!53746f72-6167-11aa-aa11-00306543ecac"
724 An Apple Mac OS X partition that contains a HFS or HFS+ filesystem.
725 The scheme-specific types are
730 .Qq Li "!48465300-0000-11aa-aa11-00306543ecac"
733 An Apple Mac OS X partition dedicated to partition metadata that descibes
735 The scheme-specific type is
736 .Qq Li "!4c616265-6c00-11aa-aa11-00306543ecac"
739 An Apple Mac OS X partition used in a software RAID configuration.
740 The scheme-specific type is
741 .Qq Li "!52414944-0000-11aa-aa11-00306543ecac"
743 .It Cm apple-raid-offline
744 An Apple Mac OS X partition used in a software RAID configuration.
745 The scheme-specific type is
746 .Qq Li "!52414944-5f4f-11aa-aa11-00306543ecac"
748 .It Cm apple-tv-recovery
749 An Apple Mac OS X partition used by Apple TV.
750 The scheme-specific type is
751 .Qq Li "!5265636f-7665-11aa-aa11-00306543ecac"
754 An Apple Mac OS X partition that contains a UFS filesystem.
755 The scheme-specific types are
758 .Qq Li "!Apple_UNIX_SVR2"
760 .Qq Li "!55465300-0000-11aa-aa11-00306543ecac"
763 An Apple Mac OS X partition that contains a ZFS volume.
764 The scheme-specific type is
765 .Qq Li "!6a898cc3-1dd2-11b2-99a6-080020736631"
766 for GPT. The same GUID is being used also for
767 .Sy illumos/Solaris /usr partition .
771 .It Cm dragonfly-label32
772 A DragonFlyBSD partition subdivided into filesystems with a
775 The scheme-specific type is
776 .Qq Li "!9d087404-1ca5-11dc-8817-01301bb8a9f5"
778 .It Cm dragonfly-label64
779 A DragonFlyBSD partition subdivided into filesystems with a
781 The scheme-specific type is
782 .Qq Li "!3d48ce54-1d16-11dc-8696-01301bb8a9f5"
784 .It Cm dragonfly-legacy
785 A legacy partition type used in DragonFlyBSD.
786 The scheme-specific type is
787 .Qq Li "!bd215ab2-1d16-11dc-8696-01301bb8a9f5"
790 A DragonFlyBSD partition used with Concatenated Disk driver.
791 The scheme-specific type is
792 .Qq Li "!dbd5211b-1ca5-11dc-8817-01301bb8a9f5"
794 .It Cm dragonfly-hammer
795 A DragonFlyBSD partition that contains a Hammer filesystem.
796 The scheme-specific type is
797 .Qq Li "!61dc63ac-6e38-11dc-8513-01301bb8a9f5"
799 .It Cm dragonfly-hammer2
800 A DragonFlyBSD partition that contains a Hammer2 filesystem.
801 The scheme-specific type is
802 .Qq Li "!5cbb9ad1-862d-11dc-a94d-01301bb8a9f5"
804 .It Cm dragonfly-swap
805 A DragonFlyBSD partition dedicated to swap space.
806 The scheme-specific type is
807 .Qq Li "!9d58fdbd-1ca5-11dc-8817-01301bb8a9f5"
810 A DragonFlyBSD partition that contains an UFS1 filesystem.
811 The scheme-specific type is
812 .Qq Li "!9d94ce7c-1ca5-11dc-8817-01301bb8a9f5"
814 .It Cm dragonfly-vinum
815 A DragonFlyBSD partition used with Logical Volume Manager.
816 The scheme-specific type is
817 .Qq Li "!9dd4478f-1ca5-11dc-8817-01301bb8a9f5"
820 A partition subdivided into filesystems with a EBR.
821 The scheme-specific type is
825 A partition that contains a FAT16 filesystem.
826 The scheme-specific type is
830 A partition that contains a FAT32 filesystem.
831 The scheme-specific type is
835 A partition that contains a FAT32 (LBA) filesystem.
836 The scheme-specific type is
840 A Linux partition that contains some filesystem with data.
841 The scheme-specific types are
844 .Qq Li "!0fc63daf-8483-4772-8e79-3d69d8477de4"
847 A Linux partition dedicated to Logical Volume Manager.
848 The scheme-specific types are
851 .Qq Li "!e6d6d379-f507-44c2-a23c-238f2a3df928"
854 A Linux partition used in a software RAID configuration.
855 The scheme-specific types are
858 .Qq Li "!a19d880f-05fc-4d3b-a006-743f0f84911e"
861 A Linux partition dedicated to swap space.
862 The scheme-specific types are
865 .Qq Li "!0657fd6d-a4ab-43c4-84e5-0933c84b4f4f"
868 A partition that is sub-partitioned by a Master Boot Record (MBR).
869 This type is known as
870 .Qq Li "!024dee41-33e7-11d3-9d69-0008c781f39f"
873 A basic data partition (BDP) for Microsoft operating systems.
874 In the GPT this type is the equivalent to partition types
879 This type is used for GPT exFAT partitions.
880 The scheme-specific type is
881 .Qq Li "!ebd0a0a2-b9e5-4433-87c0-68b6b72699c7"
884 A partition that contains Logical Disk Manager (LDM) volumes.
885 The scheme-specific types are
888 .Qq Li "!af9b60a0-1431-4f62-bc68-3311714a69ad"
890 .It Cm ms-ldm-metadata
891 A partition that contains Logical Disk Manager (LDM) database.
892 The scheme-specific type is
893 .Qq Li "!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3"
896 A NetBSD partition used with Concatenated Disk driver.
897 The scheme-specific type is
898 .Qq Li "!2db519c4-b10f-11dc-b99b-0019d1879648"
901 An encrypted NetBSD partition.
902 The scheme-specific type is
903 .Qq Li "!2db519ec-b10f-11dc-b99b-0019d1879648"
906 A NetBSD partition that contains an UFS filesystem.
907 The scheme-specific type is
908 .Qq Li "!49f48d5a-b10e-11dc-b99b-0019d1879648"
911 A NetBSD partition that contains an LFS filesystem.
912 The scheme-specific type is
913 .Qq Li "!49f48d82-b10e-11dc-b99b-0019d1879648"
916 A NetBSD partition used in a software RAID configuration.
917 The scheme-specific type is
918 .Qq Li "!49f48daa-b10e-11dc-b99b-0019d1879648"
921 A NetBSD partition dedicated to swap space.
922 The scheme-specific type is
923 .Qq Li "!49f48d32-b10e-11dc-b99b-0019d1879648"
926 A partition that contains a NTFS or exFAT filesystem.
927 The scheme-specific type is
931 The system partition dedicated to storing boot loaders on some PowerPC systems,
932 notably those made by IBM.
933 The scheme-specific types are
936 .Qq Li "!9e1a2d38-c612-4316-aa26-8b49521e5a8b"
939 A illumos/Solaris partition dedicated to boot loader.
940 The scheme-specific type is
941 .Qq Li "!6a82cb45-1dd2-11b2-99a6-080020736631"
944 A illumos/Solaris partition dedicated to root filesystem.
945 The scheme-specific type is
946 .Qq Li "!6a85cf4d-1dd2-11b2-99a6-080020736631"
949 A illumos/Solaris partition dedicated to swap.
950 The scheme-specific type is
951 .Qq Li "!6a87c46f-1dd2-11b2-99a6-080020736631"
953 .It Cm solaris-backup
954 A illumos/Solaris partition dedicated to backup.
955 The scheme-specific type is
956 .Qq Li "!6a8b642b-1dd2-11b2-99a6-080020736631"
959 A illumos/Solaris partition dedicated to /var filesystem.
960 The scheme-specific type is
961 .Qq Li "!6a8ef2e9-1dd2-11b2-99a6-080020736631"
964 A illumos/Solaris partition dedicated to /home filesystem.
965 The scheme-specific type is
966 .Qq Li "!6a90ba39-1dd2-11b2-99a6-080020736631"
968 .It Cm solaris-altsec
969 A illumos/Solaris partition dedicated to alternate sector.
970 The scheme-specific type is
971 .Qq Li "!6a9283a5-1dd2-11b2-99a6-080020736631"
973 .It Cm solaris-reserved
974 A illumos/Solaris partition dedicated to reserved space.
975 The scheme-specific type is
976 .Qq Li "!6a945a3b-1dd2-11b2-99a6-080020736631"
979 A partition that contains a VMware File System (VMFS).
980 The scheme-specific types are
983 .Qq Li "!aa31e02a-400f-11db-9590-000c2911d1b8"
985 .It Cm vmware-vmkdiag
986 A partition that contains a VMware diagostic filesystem.
987 The scheme-specific types are
990 .Qq Li "!9d275380-40ad-11db-bf97-000c2911d1b8"
992 .It Cm vmware-reserved
993 A VMware reserved partition.
994 The scheme-specific type is
995 .Qq Li "!9198effc-31c0-11db-8f-78-000c2911d1b8"
997 .It Cm vmware-vsanhdr
998 A partition claimed by VMware VSAN.
999 The scheme-specific type is
1000 .Qq Li "!381cfccc-7288-11e0-92ee-000c2911d0b2"
1004 The scheme-specific attributes for EBR:
1005 .Bl -tag -width ".Cm active"
1009 The scheme-specific attributes for GPT:
1010 .Bl -tag -width ".Cm bootfailed"
1014 stage 1 boot loader will try to boot the system from this partition.
1015 Multiple partitions can be marked with the
1022 Setting this attribute automatically sets the
1027 stage 1 boot loader will try to boot the system from this partition only once.
1028 Multiple partitions can be marked with the
1037 This attribute should not be manually managed.
1038 It is managed by the
1040 stage 1 boot loader and the
1041 .Pa /etc/rc.d/gptboot
1047 Setting this attribute overwrites the Protective MBR with a new one where
1048 the 0xee partition is the second, rather than the first record.
1049 This resolves a BIOS compatibility issue with some Lenovo models including the
1050 X220, T420, and T520, allowing them to boot from GPT partitioned disks
1054 The scheme-specific attributes for MBR:
1055 .Bl -tag -width ".Cm active"
1060 supports several partitioning schemes and each scheme uses different
1062 The bootstrap code is located in a specific disk area for each partitioning
1063 scheme, and may vary in size for different schemes.
1065 Bootstrap code can be separated into two types.
1066 The first type is embedded in the partitioning scheme's metadata, while the
1067 second type is located on a specific partition.
1068 Embedding bootstrap code should only be done with the
1073 The GEOM PART class knows how to safely embed bootstrap code into
1074 specific partitioning scheme metadata without causing any damage.
1076 The Master Boot Record (MBR) uses a 512-byte bootstrap code image, embedded
1077 into the partition table's metadata area.
1078 There are two variants of this bootstrap code:
1083 searches for a partition with the
1087 section) in the partition table.
1088 Then it runs next bootstrap stage.
1091 image contains a boot manager with some additional interactive functions
1092 for multi-booting from a user-selected partition.
1094 A BSD disklabel is usually created inside an MBR partition (slice)
1098 .Sx "PARTITION TYPES"
1100 It uses 8 KB size bootstrap code image
1102 embedded into the partition table's metadata area.
1104 Both types of bootstrap code are used to boot from the GUID Partition Table.
1105 First, a protective MBR is embedded into the first disk sector from the
1108 It searches through the GPT for a
1111 .Sx "PARTITION TYPES"
1112 section) and runs the next bootstrap stage from it.
1115 partition should be smaller than 545 KB.
1116 It can be located either before or after other
1118 partitions on the disk.
1119 There are two variants of bootstrap code to write to this partition:
1122 .Pa /boot/gptzfsboot .
1125 is used to boot from UFS partitions.
1129 partitions in the GPT and selects one to boot based on the
1134 If neither attribute is found,
1136 boots from the first
1140 .Pq the third bootstrap stage
1141 is loaded from the first partition that matches these conditions.
1144 for more information.
1146 .Pa /boot/gptzfsboot
1147 is used to boot from ZFS.
1148 It searches through the GPT for
1150 partitions, trying to detect ZFS pools.
1151 After all pools are detected,
1153 is started from the first one found set as bootable.
1155 The VTOC8 scheme does not support embedding bootstrap code.
1156 Instead, the 8 KBytes bootstrap code image
1158 should be written with the
1162 option to all sufficiently large VTOC8 partitions.
1165 option could be omitted.
1167 The APM scheme also does not support embedding bootstrap code.
1168 Instead, the 800 KBytes bootstrap code image
1170 should be written with the
1172 command to a partition of type
1174 which should also be 800 KB in size.
1175 .Sh OPERATIONAL FLAGS
1176 Actions other than the
1180 actions take an optional
1183 This option is used to specify action-specific operational flags.
1188 flag so that the action is immediately
1190 The user can specify
1192 to have the action result in a pending change that can later, with
1193 other pending changes, be committed as a single compound change with
1196 action or reverted with the
1200 The GEOM PART class supports recovering of partition tables only for GPT.
1201 The GPT primary metadata is stored at the beginning of the device.
1202 For redundancy, a secondary
1204 copy of the metadata is stored at the end of the device.
1205 As a result of having two copies, some corruption of metadata is not
1206 fatal to the working of GPT.
1207 When the kernel detects corrupt metadata, it marks this table as corrupt
1208 and reports the problem.
1212 are the only operations allowed on corrupt tables.
1214 If one GPT header appears to be corrupt but the other copy remains intact,
1215 the kernel will log the following:
1216 .Bd -literal -offset indent
1217 GEOM: provider: the primary GPT table is corrupt or invalid.
1218 GEOM: provider: using the secondary instead -- recovery strongly advised.
1222 .Bd -literal -offset indent
1223 GEOM: provider: the secondary GPT table is corrupt or invalid.
1224 GEOM: provider: using the primary only -- recovery suggested.
1233 will report about corrupt tables.
1235 If the size of the device has changed (e.g.,\& volume expansion) the
1236 secondary GPT header will no longer be located in the last sector.
1237 This is not a metadata corruption, but it is dangerous because any
1238 corruption of the primary GPT will lead to loss of the partition table.
1239 This problem is reported by the kernel with the message:
1240 .Bd -literal -offset indent
1241 GEOM: provider: the secondary GPT header is not in the last LBA.
1244 This situation can be recovered with the
1247 This command reconstructs the corrupt metadata using known valid
1248 metadata and relocates the secondary GPT to the end of the device.
1251 The GEOM PART class can detect the same partition table visible through
1252 different GEOM providers, and some of them will be marked as corrupt.
1253 Be careful when choosing a provider for recovery.
1254 If you choose incorrectly you can destroy the metadata of another GEOM class,
1255 e.g.,\& GEOM MIRROR or GEOM LABEL.
1256 .Sh SYSCTL VARIABLES
1259 variables can be used to control the behavior of the
1262 The default value is shown next to each variable.
1263 .Bl -tag -width indent
1264 .It Va kern.geom.part.allow_nesting : No 0
1265 By default, some schemes (currently BSD, BSD64 and VTOC8) do not permit
1266 further nested partitioning.
1267 This variable overrides this restriction and allows arbitrary nesting (except
1268 within partitions created at offset 0).
1269 Some schemes have their own separate checks, for which see below.
1270 .It Va kern.geom.part.auto_resize : No 1
1271 This variable controls automatic resize behavior of the
1274 When this variable is enable and new size of provider is detected, the schema
1275 metadata is resized but all changes are not saved to disk, until
1277 is run to confirm changes.
1278 This behavior is also reported with diagnostic message:
1279 .Sy "GEOM_PART: (provider) was automatically resized."
1280 .Sy "Use `gpart commit (provider)` to save changes or `gpart undo (provider)`"
1281 .Sy "to revert them."
1282 .It Va kern.geom.part.check_integrity : No 1
1283 This variable controls the behaviour of metadata integrity checks.
1284 When integrity checks are enabled, the
1286 GEOM class verifies all generic partition parameters obtained from the
1288 If some inconsistency is detected, the partition table will be
1289 rejected with a diagnostic message:
1290 .Sy "GEOM_PART: Integrity check failed (provider, scheme)" .
1291 .It Va kern.geom.part.gpt.allow_nesting : No 0
1292 By default the GPT scheme is allowed only at the outermost nesting level.
1293 This variable allows this restriction to be removed.
1294 .It Va kern.geom.part.ldm.debug : No 0
1295 Debug level of the Logical Disk Manager (LDM) module.
1296 This can be set to a number between 0 and 2 inclusive.
1297 If set to 0 minimal debug information is printed,
1298 and if set to 2 the maximum amount of debug information is printed.
1299 .It Va kern.geom.part.ldm.show_mirrors : No 0
1300 This variable controls how the Logical Disk Manager (LDM) module handles
1302 By default mirrored volumes are shown as partitions with type
1305 .Sx "PARTITION TYPES"
1307 If this variable set to 1 each component of the mirrored volume will be
1308 present as independent partition.
1310 This may break a mirrored volume and lead to data damage.
1311 .It Va kern.geom.part.mbr.enforce_chs : No 0
1312 Specify how the Master Boot Record (MBR) module does alignment.
1313 If this variable is set to a non-zero value, the module will automatically
1314 recalculate the user-specified offset and size for alignment with the CHS
1316 Otherwise the values will be left unchanged.
1317 .It Va kern.geom.part.separator : No ""
1318 Specify an optional separator that will be inserted between the GEOM name
1323 Note that setting this variable may break software which assumes a particular
1327 Exit status is 0 on success, and 1 if the command fails.
1329 The examples below assume that the disk's logical block size is 512
1330 bytes, regardless of its physical block size.
1332 In this example, we will format
1334 with the GPT scheme and create boot, swap and root partitions.
1335 First, we need to create the partition table:
1336 .Bd -literal -offset indent
1337 /sbin/gpart create -s GPT ada0
1340 Next, we install a protective MBR with the first-stage bootstrap code.
1341 The protective MBR lists a single, bootable partition spanning the
1342 entire disk, thus allowing non-GPT-aware BIOSes to boot from the disk
1343 and preventing tools which do not understand the GPT scheme from
1344 considering the disk to be unformatted.
1345 .Bd -literal -offset indent
1346 /sbin/gpart bootcode -b /boot/pmbr ada0
1349 We then create a dedicated
1351 partition to hold the second-stage boot loader, which will load the
1353 kernel and modules from a UFS or ZFS filesystem.
1354 This partition must be larger than the bootstrap code
1359 .Pa /boot/gptzfsboot
1362 but smaller than 545 kB since the first-stage loader will load the
1363 entire partition into memory during boot, regardless of how much data
1364 it actually contains.
1365 We create a 472-block (236 kB) boot partition at offset 40, which is
1366 the size of the partition table (34 blocks or 17 kB) rounded up to the
1367 nearest 4 kB boundary.
1368 .Bd -literal -offset indent
1369 /sbin/gpart add -b 40 -s 472 -t freebsd-boot ada0
1370 /sbin/gpart bootcode -p /boot/gptboot -i 1 ada0
1373 We now create a 4 GB swap partition at the first available offset,
1374 which is 40 + 472 = 512 blocks (256 kB).
1375 .Bd -literal -offset indent
1376 /sbin/gpart add -s 4G -t freebsd-swap ada0
1379 Aligning the swap partition and all subsequent partitions on a 256 kB
1380 boundary ensures optimal performance on a wide range of media, from
1381 plain old disks with 512-byte blocks, through modern
1383 disks with 4096-byte physical blocks, to RAID volumes with stripe
1384 sizes of up to 256 kB.
1386 Finally, we create and format an 8 GB
1388 partition for the root filesystem, leaving the rest of the slice free
1389 for additional filesystems:
1390 .Bd -literal -offset indent
1391 /sbin/gpart add -s 8G -t freebsd-ufs ada0
1392 /sbin/newfs -Uj /dev/ada0p3
1395 In this example, we will format
1397 with the MBR scheme and create a single partition which we subdivide
1402 First, we create the partition table and a single 64 GB partition,
1403 then we mark that partition active (bootable) and install the
1404 first-stage boot loader:
1405 .Bd -literal -offset indent
1406 /sbin/gpart create -s MBR ada0
1407 /sbin/gpart add -t freebsd -s 64G ada0
1408 /sbin/gpart set -a active -i 1 ada0
1409 /sbin/gpart bootcode -b /boot/boot0 ada0
1412 Next, we create a disklabel in that partition
1415 in disklabel terminology
1417 with room for up to 20 partitions:
1418 .Bd -literal -offset indent
1419 /sbin/gpart create -s BSD -n 20 ada0s1
1422 We then create an 8 GB root partition and a 4 GB swap partition:
1423 .Bd -literal -offset indent
1424 /sbin/gpart add -t freebsd-ufs -s 8G ada0s1
1425 /sbin/gpart add -t freebsd-swap -s 4G ada0s1
1428 Finally, we install the appropriate boot loader for the
1431 .Bd -literal -offset indent
1432 /sbin/gpart bootcode -b /boot/boot ada0s1
1436 Create a VTOC8 scheme on
1438 .Bd -literal -offset indent
1439 /sbin/gpart create -s VTOC8 da0
1442 Create a 512MB-sized
1444 partition to contain a UFS filesystem from which the system can boot.
1445 .Bd -literal -offset indent
1446 /sbin/gpart add -s 512M -t freebsd-ufs da0
1451 partition to contain a UFS filesystem and aligned on 4KB boundaries:
1452 .Bd -literal -offset indent
1453 /sbin/gpart add -s 15G -t freebsd-ufs -a 4k da0
1456 After creating all required partitions, embed bootstrap code into them:
1457 .Bd -literal -offset indent
1458 /sbin/gpart bootcode -p /boot/boot1 da0
1460 .Ss Deleting Partitions and Destroying the Partitioning Scheme
1463 error is shown when trying to destroy a partition table, remember that
1464 all of the partitions must be deleted first with the
1469 has three partitions:
1470 .Bd -literal -offset indent
1471 /sbin/gpart delete -i 3 da0
1472 /sbin/gpart delete -i 2 da0
1473 /sbin/gpart delete -i 1 da0
1474 /sbin/gpart destroy da0
1477 Rather than deleting each partition and then destroying the partitioning
1480 option can be given with
1482 to delete all of the partitions before destroying the partitioning scheme.
1483 This is equivalent to the previous example:
1484 .Bd -literal -offset indent
1485 /sbin/gpart destroy -F da0
1487 .Ss Backup and Restore
1489 Create a backup of the partition table from
1491 .Bd -literal -offset indent
1492 /sbin/gpart backup da0 > da0.backup
1495 Restore the partition table from the backup to
1497 .Bd -literal -offset indent
1498 /sbin/gpart restore -l da0 < /mnt/da0.backup
1501 Clone the partition table from
1507 .Bd -literal -offset indent
1508 /sbin/gpart backup ada0 | /sbin/gpart restore -F ada1 ada2
1522 .An Marcel Moolenaar Aq Mt marcel@FreeBSD.org
1526 (6a898cc3-1dd2-11b2-99a6-080020736631) is also being used
1527 on illumos/Solaris platforms for ZFS volumes.