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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 Do not 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 skips preservation to help with some versions of
225 that do not 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.
556 usually used to subdivide MBR partitions.
558 This scheme can also be used as the sole partitioning method, without
560 Partition editing tools from other operating systems often do not
561 understand the bare disklabel partition layout, so this is sometimes
563 .Dq dangerously dedicated .
569 64-bit implementation of BSD disklabel used in
577 The Logical Disk Manager is an implementation of volume manager for
578 Microsoft Windows NT.
583 GUID Partition Table is used on Intel-based Macintosh computers and
584 gradually replacing MBR on most PCs and other systems.
589 Master Boot Record is used on PCs and removable media.
595 option adds support for the Extended Boot Record (EBR),
596 which is used to define a logical partition.
598 .Cm GEOM_PART_EBR_COMPAT
599 option enables backward compatibility for partition names
601 It also prevents any type of actions on such partitions.
603 Sun's SMI Volume Table Of Contents, used by
615 for additional information on labelization of devices and partitions.
617 Partition types are identified on disk by particular strings or magic
621 utility uses symbolic names for common partition types so the user
622 does not need to know these values or other details of the partitioning
626 utility also allows the user to specify scheme-specific partition types
627 for partition types that do not have symbolic names.
628 Symbolic names currently understood and used by
631 .Bl -tag -width ".Cm dragonfly-disklabel64"
633 The system partition dedicated to storing boot loaders on some Apple
635 The scheme-specific types are
638 .Qq Li "!Apple_Bootstrap"
640 .Qq Li "!426f6f74-0000-11aa-aa11-00306543ecac"
643 The system partition dedicated to second stage of the boot loader program.
644 Usually it is used by the GRUB 2 loader for GPT partitioning schemes.
645 The scheme-specific type is
646 .Qq Li "!21686148-6449-6E6F-744E-656564454649" .
648 The system partition for computers that use the Extensible Firmware
650 The scheme-specific types are
653 .Qq Li "!c12a7328-f81f-11d2-ba4b-00a0c93ec93b"
658 partition subdivided into filesystems with a
661 This is a legacy partition type and should not be used for the APM
663 The scheme-specific types are
668 .Qq Li "!516e7cb4-6ecf-11d6-8ff8-00022d09712b"
673 partition dedicated to bootstrap code.
674 The scheme-specific type is
675 .Qq Li "!83bd6b9d-7f41-11dc-be0b-001560b84f0f"
680 partition dedicated to swap space.
681 The scheme-specific types are
682 .Qq Li "!FreeBSD-swap"
684 .Qq Li "!516e7cb5-6ecf-11d6-8ff8-00022d09712b"
685 for GPT, and tag 0x0901 for VTOC8.
689 partition that contains a UFS or UFS2 filesystem.
690 The scheme-specific types are
691 .Qq Li "!FreeBSD-UFS"
693 .Qq Li "!516e7cb6-6ecf-11d6-8ff8-00022d09712b"
694 for GPT, and tag 0x0902 for VTOC8.
698 partition that contains a Vinum volume.
699 The scheme-specific types are
700 .Qq Li "!FreeBSD-Vinum"
702 .Qq Li "!516e7cb8-6ecf-11d6-8ff8-00022d09712b"
703 for GPT, and tag 0x0903 for VTOC8.
707 partition that contains a ZFS volume.
708 The scheme-specific types are
709 .Qq Li "!FreeBSD-ZFS"
711 .Qq Li "!516e7cba-6ecf-11d6-8ff8-00022d09712b"
712 for GPT, and 0x0904 for VTOC8.
715 Other symbolic names that can be used with the
718 .Bl -tag -width ".Cm dragonfly-disklabel64"
720 An Apple macOS partition used for the Apple file system, APFS.
721 .It Cm apple-core-storage
722 An Apple Mac OS X partition used by logical volume manager known as
724 The scheme-specific type is
725 .Qq Li "!53746f72-6167-11aa-aa11-00306543ecac"
728 An Apple Mac OS X partition that contains a HFS or HFS+ filesystem.
729 The scheme-specific types are
734 .Qq Li "!48465300-0000-11aa-aa11-00306543ecac"
737 An Apple Mac OS X partition dedicated to partition metadata that descibes
739 The scheme-specific type is
740 .Qq Li "!4c616265-6c00-11aa-aa11-00306543ecac"
743 An Apple Mac OS X partition used in a software RAID configuration.
744 The scheme-specific type is
745 .Qq Li "!52414944-0000-11aa-aa11-00306543ecac"
747 .It Cm apple-raid-offline
748 An Apple Mac OS X partition used in a software RAID configuration.
749 The scheme-specific type is
750 .Qq Li "!52414944-5f4f-11aa-aa11-00306543ecac"
752 .It Cm apple-tv-recovery
753 An Apple Mac OS X partition used by Apple TV.
754 The scheme-specific type is
755 .Qq Li "!5265636f-7665-11aa-aa11-00306543ecac"
758 An Apple Mac OS X partition that contains a UFS filesystem.
759 The scheme-specific types are
762 .Qq Li "!Apple_UNIX_SVR2"
764 .Qq Li "!55465300-0000-11aa-aa11-00306543ecac"
767 An Apple Mac OS X partition that contains a ZFS volume.
768 The scheme-specific type is
769 .Qq Li "!6a898cc3-1dd2-11b2-99a6-080020736631"
771 The same GUID is being used also for
772 .Sy illumos/Solaris /usr partition .
776 .It Cm dragonfly-label32
779 partition subdivided into filesystems with a
782 The scheme-specific type is
783 .Qq Li "!9d087404-1ca5-11dc-8817-01301bb8a9f5"
785 .It Cm dragonfly-label64
788 partition subdivided into filesystems with a
790 The scheme-specific type is
791 .Qq Li "!3d48ce54-1d16-11dc-8696-01301bb8a9f5"
793 .It Cm dragonfly-legacy
794 A legacy partition type used in
796 The scheme-specific type is
797 .Qq Li "!bd215ab2-1d16-11dc-8696-01301bb8a9f5"
802 partition used with Concatenated Disk driver.
803 The scheme-specific type is
804 .Qq Li "!dbd5211b-1ca5-11dc-8817-01301bb8a9f5"
806 .It Cm dragonfly-hammer
809 partition that contains a Hammer filesystem.
810 The scheme-specific type is
811 .Qq Li "!61dc63ac-6e38-11dc-8513-01301bb8a9f5"
813 .It Cm dragonfly-hammer2
816 partition that contains a Hammer2 filesystem.
817 The scheme-specific type is
818 .Qq Li "!5cbb9ad1-862d-11dc-a94d-01301bb8a9f5"
820 .It Cm dragonfly-swap
823 partition dedicated to swap space.
824 The scheme-specific type is
825 .Qq Li "!9d58fdbd-1ca5-11dc-8817-01301bb8a9f5"
830 partition that contains an UFS1 filesystem.
831 The scheme-specific type is
832 .Qq Li "!9d94ce7c-1ca5-11dc-8817-01301bb8a9f5"
834 .It Cm dragonfly-vinum
837 partition used with Logical Volume Manager.
838 The scheme-specific type is
839 .Qq Li "!9dd4478f-1ca5-11dc-8817-01301bb8a9f5"
842 A partition subdivided into filesystems with a EBR.
843 The scheme-specific type is
847 A partition that contains a FAT16 filesystem.
848 The scheme-specific type is
852 A partition that contains a FAT32 filesystem.
853 The scheme-specific type is
857 A partition that contains a FAT32 (LBA) filesystem.
858 The scheme-specific type is
862 A raw partition containing a HiFive first stage bootloader.
863 The scheme-specific type is
864 .Qq Li "!5b193300-fc78-40cd-8002-e86c45580b47"
867 A raw partition containing a HiFive second stage bootloader.
868 The scheme-specific type is
869 .Qq Li "!2e54b353-1271-4842-806f-e436d6af6985"
872 A Linux partition that contains some filesystem with data.
873 The scheme-specific types are
876 .Qq Li "!0fc63daf-8483-4772-8e79-3d69d8477de4"
879 A Linux partition dedicated to Logical Volume Manager.
880 The scheme-specific types are
883 .Qq Li "!e6d6d379-f507-44c2-a23c-238f2a3df928"
886 A Linux partition used in a software RAID configuration.
887 The scheme-specific types are
890 .Qq Li "!a19d880f-05fc-4d3b-a006-743f0f84911e"
893 A Linux partition dedicated to swap space.
894 The scheme-specific types are
897 .Qq Li "!0657fd6d-a4ab-43c4-84e5-0933c84b4f4f"
900 A partition that is sub-partitioned by a Master Boot Record (MBR).
901 This type is known as
902 .Qq Li "!024dee41-33e7-11d3-9d69-0008c781f39f"
905 A basic data partition (BDP) for Microsoft operating systems.
906 In the GPT this type is the equivalent to partition types
911 This type is used for GPT exFAT partitions.
912 The scheme-specific type is
913 .Qq Li "!ebd0a0a2-b9e5-4433-87c0-68b6b72699c7"
916 A partition that contains Logical Disk Manager (LDM) volumes.
917 The scheme-specific types are
920 .Qq Li "!af9b60a0-1431-4f62-bc68-3311714a69ad"
922 .It Cm ms-ldm-metadata
923 A partition that contains Logical Disk Manager (LDM) database.
924 The scheme-specific type is
925 .Qq Li "!5808c8aa-7e8f-42e0-85d2-e1e90434cfb3"
930 partition used with Concatenated Disk driver.
931 The scheme-specific type is
932 .Qq Li "!2db519c4-b10f-11dc-b99b-0019d1879648"
938 The scheme-specific type is
939 .Qq Li "!2db519ec-b10f-11dc-b99b-0019d1879648"
944 partition that contains an UFS filesystem.
945 The scheme-specific type is
946 .Qq Li "!49f48d5a-b10e-11dc-b99b-0019d1879648"
951 partition that contains an LFS filesystem.
952 The scheme-specific type is
953 .Qq Li "!49f48d82-b10e-11dc-b99b-0019d1879648"
958 partition used in a software RAID configuration.
959 The scheme-specific type is
960 .Qq Li "!49f48daa-b10e-11dc-b99b-0019d1879648"
965 partition dedicated to swap space.
966 The scheme-specific type is
967 .Qq Li "!49f48d32-b10e-11dc-b99b-0019d1879648"
970 A partition that contains a NTFS or exFAT filesystem.
971 The scheme-specific type is
975 The system partition dedicated to storing boot loaders on some PowerPC systems,
976 notably those made by IBM.
977 The scheme-specific types are
980 .Qq Li "!9e1a2d38-c612-4316-aa26-8b49521e5a8b"
983 A illumos/Solaris partition dedicated to boot loader.
984 The scheme-specific type is
985 .Qq Li "!6a82cb45-1dd2-11b2-99a6-080020736631"
988 A illumos/Solaris partition dedicated to root filesystem.
989 The scheme-specific type is
990 .Qq Li "!6a85cf4d-1dd2-11b2-99a6-080020736631"
993 A illumos/Solaris partition dedicated to swap.
994 The scheme-specific type is
995 .Qq Li "!6a87c46f-1dd2-11b2-99a6-080020736631"
997 .It Cm solaris-backup
998 A illumos/Solaris partition dedicated to backup.
999 The scheme-specific type is
1000 .Qq Li "!6a8b642b-1dd2-11b2-99a6-080020736631"
1003 A illumos/Solaris partition dedicated to /var filesystem.
1004 The scheme-specific type is
1005 .Qq Li "!6a8ef2e9-1dd2-11b2-99a6-080020736631"
1008 A illumos/Solaris partition dedicated to /home filesystem.
1009 The scheme-specific type is
1010 .Qq Li "!6a90ba39-1dd2-11b2-99a6-080020736631"
1012 .It Cm solaris-altsec
1013 A illumos/Solaris partition dedicated to alternate sector.
1014 The scheme-specific type is
1015 .Qq Li "!6a9283a5-1dd2-11b2-99a6-080020736631"
1017 .It Cm solaris-reserved
1018 A illumos/Solaris partition dedicated to reserved space.
1019 The scheme-specific type is
1020 .Qq Li "!6a945a3b-1dd2-11b2-99a6-080020736631"
1023 A partition that contains a VMware File System (VMFS).
1024 The scheme-specific types are
1027 .Qq Li "!aa31e02a-400f-11db-9590-000c2911d1b8"
1029 .It Cm vmware-vmkdiag
1030 A partition that contains a VMware diagostic filesystem.
1031 The scheme-specific types are
1034 .Qq Li "!9d275380-40ad-11db-bf97-000c2911d1b8"
1036 .It Cm vmware-reserved
1037 A VMware reserved partition.
1038 The scheme-specific type is
1039 .Qq Li "!9198effc-31c0-11db-8f-78-000c2911d1b8"
1041 .It Cm vmware-vsanhdr
1042 A partition claimed by VMware VSAN.
1043 The scheme-specific type is
1044 .Qq Li "!381cfccc-7288-11e0-92ee-000c2911d0b2"
1048 The scheme-specific attributes for EBR:
1049 .Bl -tag -width ".Cm active"
1053 The scheme-specific attributes for GPT:
1054 .Bl -tag -width ".Cm bootfailed"
1058 stage 1 boot loader will try to boot the system from this partition.
1059 Multiple partitions can be marked with the
1066 Setting this attribute automatically sets the
1071 stage 1 boot loader will try to boot the system from this partition only once.
1072 Multiple partitions can be marked with the
1081 This attribute should not be manually managed.
1082 It is managed by the
1084 stage 1 boot loader and the
1085 .Pa /etc/rc.d/gptboot
1091 Setting this attribute overwrites the Protective MBR with a new one where
1092 the 0xee partition is the second, rather than the first record.
1093 This resolves a BIOS compatibility issue with some Lenovo models including the
1094 X220, T420, and T520, allowing them to boot from GPT partitioned disks
1098 The scheme-specific attributes for MBR:
1099 .Bl -tag -width ".Cm active"
1104 supports several partitioning schemes and each scheme uses different
1106 The bootstrap code is located in a specific disk area for each partitioning
1107 scheme, and may vary in size for different schemes.
1109 Bootstrap code can be separated into two types.
1110 The first type is embedded in the partitioning scheme's metadata, while the
1111 second type is located on a specific partition.
1112 Embedding bootstrap code should only be done with the
1117 The GEOM PART class knows how to safely embed bootstrap code into
1118 specific partitioning scheme metadata without causing any damage.
1120 The Master Boot Record (MBR) uses a 512-byte bootstrap code image, embedded
1121 into the partition table's metadata area.
1122 There are two variants of this bootstrap code:
1127 searches for a partition with the
1131 section) in the partition table.
1132 Then it runs next bootstrap stage.
1135 image contains a boot manager with some additional interactive functions
1136 for multi-booting from a user-selected partition.
1138 A BSD disklabel is usually created inside an MBR partition (slice)
1142 .Sx "PARTITION TYPES"
1144 It uses 8 KB size bootstrap code image
1146 embedded into the partition table's metadata area.
1148 Both types of bootstrap code are used to boot from the GUID Partition Table.
1149 First, a protective MBR is embedded into the first disk sector from the
1152 It searches through the GPT for a
1155 .Sx "PARTITION TYPES"
1156 section) and runs the next bootstrap stage from it.
1159 partition should be smaller than 545 KB.
1160 It can be located either before or after other
1162 partitions on the disk.
1163 There are two variants of bootstrap code to write to this partition:
1166 .Pa /boot/gptzfsboot .
1169 is used to boot from UFS partitions.
1173 partitions in the GPT and selects one to boot based on the
1178 If neither attribute is found,
1180 boots from the first
1184 .Pq the third bootstrap stage
1185 is loaded from the first partition that matches these conditions.
1188 for more information.
1190 .Pa /boot/gptzfsboot
1191 is used to boot from ZFS.
1192 It searches through the GPT for
1194 partitions, trying to detect ZFS pools.
1195 After all pools are detected,
1197 is started from the first one found set as bootable.
1199 The VTOC8 scheme does not support embedding bootstrap code.
1200 Instead, the 8 KBytes bootstrap code image
1202 should be written with the
1206 option to all sufficiently large VTOC8 partitions.
1209 option could be omitted.
1211 The APM scheme also does not support embedding bootstrap code.
1212 Instead, the 800 KBytes bootstrap code image
1214 should be written with the
1216 command to a partition of type
1218 which should also be 800 KB in size.
1219 .Sh OPERATIONAL FLAGS
1220 Actions other than the
1224 actions take an optional
1227 This option is used to specify action-specific operational flags.
1232 flag so that the action is immediately
1234 The user can specify
1236 to have the action result in a pending change that can later, with
1237 other pending changes, be committed as a single compound change with
1240 action or reverted with the
1244 The GEOM PART class supports recovering of partition tables only for GPT.
1245 The GPT primary metadata is stored at the beginning of the device.
1246 For redundancy, a secondary
1248 copy of the metadata is stored at the end of the device.
1249 As a result of having two copies, some corruption of metadata is not
1250 fatal to the working of GPT.
1251 When the kernel detects corrupt metadata, it marks this table as corrupt
1252 and reports the problem.
1256 are the only operations allowed on corrupt tables.
1258 If one GPT header appears to be corrupt but the other copy remains intact,
1259 the kernel will log the following:
1260 .Bd -literal -offset indent
1261 GEOM: provider: the primary GPT table is corrupt or invalid.
1262 GEOM: provider: using the secondary instead -- recovery strongly advised.
1266 .Bd -literal -offset indent
1267 GEOM: provider: the secondary GPT table is corrupt or invalid.
1268 GEOM: provider: using the primary only -- recovery suggested.
1277 will report about corrupt tables.
1279 If the size of the device has changed (e.g.,\& volume expansion) the
1280 secondary GPT header will no longer be located in the last sector.
1281 This is not a metadata corruption, but it is dangerous because any
1282 corruption of the primary GPT will lead to loss of the partition table.
1283 This problem is reported by the kernel with the message:
1284 .Bd -literal -offset indent
1285 GEOM: provider: the secondary GPT header is not in the last LBA.
1288 This situation can be recovered with the
1291 This command reconstructs the corrupt metadata using known valid
1292 metadata and relocates the secondary GPT to the end of the device.
1295 The GEOM PART class can detect the same partition table visible through
1296 different GEOM providers, and some of them will be marked as corrupt.
1297 Be careful when choosing a provider for recovery.
1298 If you choose incorrectly you can destroy the metadata of another GEOM class,
1299 e.g.,\& GEOM MIRROR or GEOM LABEL.
1300 .Sh SYSCTL VARIABLES
1303 variables can be used to control the behavior of the
1306 The default value is shown next to each variable.
1307 .Bl -tag -width indent
1308 .It Va kern.geom.part.allow_nesting : No 0
1309 By default, some schemes (currently BSD, BSD64 and VTOC8) do not permit
1310 further nested partitioning.
1311 This variable overrides this restriction and allows arbitrary nesting (except
1312 within partitions created at offset 0).
1313 Some schemes have their own separate checks, for which see below.
1314 .It Va kern.geom.part.auto_resize : No 1
1315 This variable controls automatic resize behavior of the
1318 When this variable is enable and new size of provider is detected, the schema
1319 metadata is resized but all changes are not saved to disk, until
1321 is run to confirm changes.
1322 This behavior is also reported with diagnostic message:
1323 .Sy "GEOM_PART: (provider) was automatically resized."
1324 .Sy "Use `gpart commit (provider)` to save changes or `gpart undo (provider)`"
1325 .Sy "to revert them."
1326 .It Va kern.geom.part.check_integrity : No 1
1327 This variable controls the behaviour of metadata integrity checks.
1328 When integrity checks are enabled, the
1330 GEOM class verifies all generic partition parameters obtained from the
1332 If some inconsistency is detected, the partition table will be
1333 rejected with a diagnostic message:
1334 .Sy "GEOM_PART: Integrity check failed (provider, scheme)" .
1335 .It Va kern.geom.part.gpt.allow_nesting : No 0
1336 By default the GPT scheme is allowed only at the outermost nesting level.
1337 This variable allows this restriction to be removed.
1338 .It Va kern.geom.part.ldm.debug : No 0
1339 Debug level of the Logical Disk Manager (LDM) module.
1340 This can be set to a number between 0 and 2 inclusive.
1341 If set to 0 minimal debug information is printed,
1342 and if set to 2 the maximum amount of debug information is printed.
1343 .It Va kern.geom.part.ldm.show_mirrors : No 0
1344 This variable controls how the Logical Disk Manager (LDM) module handles
1346 By default mirrored volumes are shown as partitions with type
1349 .Sx "PARTITION TYPES"
1351 If this variable set to 1 each component of the mirrored volume will be
1352 present as independent partition.
1354 This may break a mirrored volume and lead to data damage.
1355 .It Va kern.geom.part.mbr.enforce_chs : No 0
1356 Specify how the Master Boot Record (MBR) module does alignment.
1357 If this variable is set to a non-zero value, the module will automatically
1358 recalculate the user-specified offset and size for alignment with the CHS
1360 Otherwise the values will be left unchanged.
1361 .It Va kern.geom.part.separator : No ""
1362 Specify an optional separator that will be inserted between the GEOM name
1367 Note that setting this variable may break software which assumes a particular
1371 Exit status is 0 on success, and 1 if the command fails.
1373 The examples below assume that the disk's logical block size is 512
1374 bytes, regardless of its physical block size.
1376 In this example, we will format
1378 with the GPT scheme and create boot, swap and root partitions.
1379 First, we need to create the partition table:
1380 .Bd -literal -offset indent
1381 /sbin/gpart create -s GPT ada0
1384 Next, we install a protective MBR with the first-stage bootstrap code.
1385 The protective MBR lists a single, bootable partition spanning the
1386 entire disk, thus allowing non-GPT-aware BIOSes to boot from the disk
1387 and preventing tools which do not understand the GPT scheme from
1388 considering the disk to be unformatted.
1389 .Bd -literal -offset indent
1390 /sbin/gpart bootcode -b /boot/pmbr ada0
1393 We then create a dedicated
1395 partition to hold the second-stage boot loader, which will load the
1397 kernel and modules from a UFS or ZFS filesystem.
1398 This partition must be larger than the bootstrap code
1403 .Pa /boot/gptzfsboot
1406 but smaller than 545 kB since the first-stage loader will load the
1407 entire partition into memory during boot, regardless of how much data
1408 it actually contains.
1409 We create a 472-block (236 kB) boot partition at offset 40, which is
1410 the size of the partition table (34 blocks or 17 kB) rounded up to the
1411 nearest 4 kB boundary.
1412 .Bd -literal -offset indent
1413 /sbin/gpart add -b 40 -s 472 -t freebsd-boot ada0
1414 /sbin/gpart bootcode -p /boot/gptboot -i 1 ada0
1417 We now create a 4 GB swap partition at the first available offset,
1418 which is 40 + 472 = 512 blocks (256 kB).
1419 .Bd -literal -offset indent
1420 /sbin/gpart add -s 4G -t freebsd-swap ada0
1423 Aligning the swap partition and all subsequent partitions on a 256 kB
1424 boundary ensures optimal performance on a wide range of media, from
1425 plain old disks with 512-byte blocks, through modern
1427 disks with 4096-byte physical blocks, to RAID volumes with stripe
1428 sizes of up to 256 kB.
1430 Finally, we create and format an 8 GB
1432 partition for the root filesystem, leaving the rest of the slice free
1433 for additional filesystems:
1434 .Bd -literal -offset indent
1435 /sbin/gpart add -s 8G -t freebsd-ufs ada0
1436 /sbin/newfs -Uj /dev/ada0p3
1439 In this example, we will format
1441 with the MBR scheme and create a single partition which we subdivide
1446 First, we create the partition table and a single 64 GB partition,
1447 then we mark that partition active (bootable) and install the
1448 first-stage boot loader:
1449 .Bd -literal -offset indent
1450 /sbin/gpart create -s MBR ada0
1451 /sbin/gpart add -t freebsd -s 64G ada0
1452 /sbin/gpart set -a active -i 1 ada0
1453 /sbin/gpart bootcode -b /boot/boot0 ada0
1456 Next, we create a disklabel in that partition
1459 in disklabel terminology
1461 with room for up to 20 partitions:
1462 .Bd -literal -offset indent
1463 /sbin/gpart create -s BSD -n 20 ada0s1
1466 We then create an 8 GB root partition and a 4 GB swap partition:
1467 .Bd -literal -offset indent
1468 /sbin/gpart add -t freebsd-ufs -s 8G ada0s1
1469 /sbin/gpart add -t freebsd-swap -s 4G ada0s1
1472 Finally, we install the appropriate boot loader for the
1475 .Bd -literal -offset indent
1476 /sbin/gpart bootcode -b /boot/boot ada0s1
1479 Create a VTOC8 scheme on
1481 .Bd -literal -offset indent
1482 /sbin/gpart create -s VTOC8 da0
1485 Create a 512MB-sized
1487 partition to contain a UFS filesystem from which the system can boot.
1488 .Bd -literal -offset indent
1489 /sbin/gpart add -s 512M -t freebsd-ufs da0
1494 partition to contain a UFS filesystem and aligned on 4KB boundaries:
1495 .Bd -literal -offset indent
1496 /sbin/gpart add -s 15G -t freebsd-ufs -a 4k da0
1499 After creating all required partitions, embed bootstrap code into them:
1500 .Bd -literal -offset indent
1501 /sbin/gpart bootcode -p /boot/boot1 da0
1503 .Ss Deleting Partitions and Destroying the Partitioning Scheme
1506 error is shown when trying to destroy a partition table, remember that
1507 all of the partitions must be deleted first with the
1512 has three partitions:
1513 .Bd -literal -offset indent
1514 /sbin/gpart delete -i 3 da0
1515 /sbin/gpart delete -i 2 da0
1516 /sbin/gpart delete -i 1 da0
1517 /sbin/gpart destroy da0
1520 Rather than deleting each partition and then destroying the partitioning
1523 option can be given with
1525 to delete all of the partitions before destroying the partitioning scheme.
1526 This is equivalent to the previous example:
1527 .Bd -literal -offset indent
1528 /sbin/gpart destroy -F da0
1530 .Ss Backup and Restore
1531 Create a backup of the partition table from
1533 .Bd -literal -offset indent
1534 /sbin/gpart backup da0 > da0.backup
1537 Restore the partition table from the backup to
1539 .Bd -literal -offset indent
1540 /sbin/gpart restore -l da0 < /mnt/da0.backup
1543 Clone the partition table from
1549 .Bd -literal -offset indent
1550 /sbin/gpart backup ada0 | /sbin/gpart restore -F ada1 ada2
1564 .An Marcel Moolenaar Aq Mt marcel@FreeBSD.org
1568 (6a898cc3-1dd2-11b2-99a6-080020736631) is also being used
1569 on illumos/Solaris platforms for ZFS volumes.