HP-UX 11i v3 - LVM Volume Group Version Migration (September 2010)

Volume group migration from Version 2.0 to Version 2.1

When a Version 2.0 volume group is migrated to 2.1, the device numbers of the device special files

do not change. The space required for the metadata for a 2.0 volume group is the same as a 2.1

volume group.

Volume group migration from Version 2.0 to Version 2.2

You can use the –U option when migrating to Version 2.2. For more information, see –U option support

for migration to Version 2.2 volume groups. When a Version 2.0 volume group is migrated to 2.2, the

device numbers of the device special files do not change. The size of metadata required for a

Version 2.2 volume group is greater than that of a 2.0 volume group; more space from each

physical volume is used during migration to a Version 2.2 volume group. To create additional space

for metadata of the Version 2.2 volume group, follow the steps in Metadata space requirements for

Version 2.x volume groups.

Volume group migration from Version 2.1 to Version 2.0

The maximum number of logical volumes supported by a Version 2.0 volume group is 511,

and the maximum number of physical volumes supported is 511. The migration of a Version 2.1

volume group to Version 2.0 fails if it has more than 511 logical volumes or more than 511

physical volumes.

If the lv minor number of any of the logical volumes of a Version 2.x volume group is more than 511,

vgversion fails the migration operation even though the total number of logical volumes in the

volume group is less than 511 (the maximum number of logical volumes supported by a Version 2.0

volume group). For example:

# ll /dev/vg01/lvol*

brw-r----- 1 root sys 128 0x000101 Jan 18 10:53 /dev/vg01/lvol1

brw-r----- 1 root sys 128 0x000302 Jan 18 10:54 /dev/vg01/lvol2

In the previous output, the lv minor number of lvol1 is 0x101 or 257 and the lv number of lvol2 is

0x302 or 770. Migration of volume group lvol2 to Version 2.0 will fail because the lv minor

number is greater than 511.

If the pvkey of any physical volume belonging to a Version 2.1 volume group is greater than 511,

vgversion fails in the migration to 2.0. Because the maximum supported physical volumes in a 2.0

volume group is 511, the pvkey of a physical volume can only range between 0 and 510. It is

possible to have a physical volume with a pvkey greater than 510 and the total number physical

volumes in the volume group less than 511. This happens when more than 511 physical volumes are

added to the volume group and later few physical volumes with a pvkey less than 510 are reduced

from the volume group. There is no direct command to see the pvkey of a physical volume. Currently,

lvdisplay –k –v option shows the pvkey instead of the physical volume path.

Volume group migration from Version 2.1 to Version 2.2

You can use the –U option when migrating to Version 2.2. For more information, see –U option support

for migration to Version 2.2 volume groups. All the requirements are the same as that of volume group

migration from Version 2.0 to 2.2.