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

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Using the vgversion command to perform

Logical Volume Manager (LVM) volume

group version migration

Technical white paper

Table of contents

Abstract ........................................................................................................................................ 2

Audience....................................................................................................................................... 2

Overview ...................................................................................................................................... 2

Prerequisites .................................................................................................................................. 3

Metadata space requirements for Version 2.x volume groups .............................................................. 3

Migration of volume group with bootable physical volumes ................................................................ 4

Unsupported features in Version 2.x volume groups .......................................................................... 4

–U option support for migration to Version 2.2 volume groups ............................................................ 4

How to use vgversion ...................................................................................................................... 5

Volume group migration flow ............................................................................................................ 5

Volume group migration from Version 1.0 to Version 2.x ................................................................... 7

Volume group migration from Version 2.0 to Version 2.1 ................................................................... 8

Volume group migration from Version 2.0 to Version 2.2 ................................................................... 8

Volume group migration from Version 2.1 to Version 2.0 ................................................................... 8

Volume group migration from Version 2.1 to Version 2.2 ................................................................... 8

Volume group migration from Version 2.2 to Version 2.1 ................................................................... 9

Volume group migration from Version 2.2 to Version 2.0 ................................................................... 9

Recovering from failures ................................................................................................................... 9

Reverting back to Version 1.0...................................................................................................... 10

Examples .................................................................................................................................... 10

Migrating a Version 1.0 volume group to a Version 2.x volume group ............................................... 11

Migrating a Version 2.0 volume group to Version 2.1 ..................................................................... 13

Migrating a Version 1.0 volume group to Version 2.2 with –U option ................................................ 14

Migrating a Version 2.2 volume group to Version 2.0 ..................................................................... 15

vgversion status messages .............................................................................................................. 17

For more information ..................................................................................................................... 20

Send comments to HP .................................................................................................................... 20

Summary of content (20 pages)

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Using the vgversion command to perform Logical Volume Manager (LVM) volume group version migration Technical white paper Table of contents Abstract ........................................................................................................................................ 2 Audience....................................................................................................................................... 2 Overview ......................................................................
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Abstract Beginning with the HP-UX 11i v3 March 2010 Update release, Logical Volume Manager (LVM) supports the following volume group versions: Version 2.2 (supported on HP-UX 11i v3 March 2010 Update and later) Version 2.1 (supported on HP-UX 11i v3 September 2008 Update and later) Version 2.0 (supported on HP-UX 11i v3 March 2008 Update and later) Version 1.0 (supported on all HP-UX 11i v3 releases) In this document, 2.x refers to volume group Version 2.0 and later. Version 2.
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HP recommends using vgversion to take advantage of: The new features in the newer volume group versions. The extended limits supported by the newer volume group versions. For more information on the new features and the limits supported by various volume group versions, see the LVM Version 2.0 volume groups in HP-UX 11i v3 white paper. Prerequisites To migrate a volume group from one version to another, you must meet the following prerequisites: The volume group must be deactivated during migration.
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Migration of volume group with bootable physical volumes Beginning with the HP-UX 11i v3 March 2010 Update release, Version 2.2 volume groups and 1.0 volume groups support bootable physical volumes. Version 2.0 and 2.1 volume groups do not support bootable physical volumes. Although migration from Version 1.0 to 2.x volume groups (particularly to 2.2, which supports bootable physical volume) and from Version 2.2 to 2.
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How to use vgversion To use the vgversion command, follow these steps: 1. Back up the volume group configuration using vgcfgbackup -f. If needed, you can use this command to recover the initial or original volume group configuration. Save the configuration back up file in a known location other than the default location; otherwise, it might be overwritten by a later configuration change. 2.
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2. The vgversion command creates the configuration backup file corresponding to the final volume group version and saves that as /etc/lvmconf/vgversion_vg_name/vg_name_final VG version.conf. The following is the output for this step: New Volume Group configuration for "/dev/vg01" has been saved in "/etc/lvmconf/vgversion_vg01/vg01_2.1.conf" Note At this point, the volume group is not modified. Even if the vgversion command is killed for any reason, there is no need for any recovery. 3.
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Volume group migration from Version 1.0 to Version 2.x Using the vgversion command, you can convert a Version 1.0 volume group to any supported 2.x volume group, but a 2.x volume group cannot be migrated to a 1.0 volume group. See Recovering from failures for information on how to undo the changes that were made by running the vgversion command during the migration process. If the volume group is deactivated, vgversion activates it in both the review option (-r) and during the migration operation (-v).
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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.
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Volume group migration from Version 2.2 to Version 2.1 Volume group migration from Version 2.2 to 2.1 fails if the volume group has bootable physical volumes or if a snapshot logical volume is configured for any logical volume of the volume group. The size of metadata required for a Version 2.2 volume group is greater than that of a 2.1 volume group. Therefore, volume group migration from Version 2.2 to 2.1 frees up a few extents. Run vgmodify to utilize the free space.
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The vgversion command creates two mapfiles named mapfile_vgname_VG initial VG version and mapfile_vgname_VG final VG version corresponding to initial volume group configuration and final volume group configuration, respectively. These mapfiles contain details of the logical volume names, and are equivalent to those created using the vgexport –m –f vg_name command. The restore script uses these mapfiles.
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Migrating a Version 1.0 volume group to a Version 2.x volume group Verify that all prequisites are met Run vgversion in review mode. The volume group can be active while running vgversion in review mode. If any of the migration prerequisites are not met, the review option lists them. You must correct any prerequisites that are not met. The following example shows the migration of a Version 1.
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New Volume Group configuration for "vg1" has been saved in "/etc/lvmconf/vg1.conf" Old Volume Group configuration for "vg1" has been saved in "/etc/lvmconf/vg1.conf.old" Starting the modification by writing to all Physical Volumes Applying the configuration to all Physical Volumes from "/etc/lvmconf/vg1.conf" Completed the modification process. New Volume Group configuration for "vg1" has been saved in "/etc/lvmconf/vg1.conf.old" Volume group "vg1" has been successfully changed.
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Verify the volume group # vgdisplay vg01 --- Volume groups --VG Name VG Write Access VG Status Max LV Cur LV Open LV Max PV Cur PV Act PV Max PE per PV VGDA PE Size (Mbytes) Total PE Alloc PE Free PE Total PVG Total Spare PVs Total Spare PVs in use VG Version VG Max Size VG Max Extents /dev/vg01 read/write available 2047 0 0 2048 2 2 131072 4 128 32766 0 32766 0 0 0 2.1 32766g 262128 This completes the migration of a volume group from Version 1.0 to 2.1. Migrating a Version 2.0 volume group to Version 2.
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Migrating a Version 1.0 volume group to Version 2.2 with –U option Verify that all prequisites are met # vgversion -r -U 1024 -V 2.2 vg01 2 free user extents from the end of the Physical Volume /dev/disk/disk13 will be utilized to accommodate the Volume Group Version 2.2 metadata. Volume Group version can be successfully changed to 2.2 Review complete. Volume group not modified Perform the migration # vgchange -a n vg01 Volume group "vg01" has been successfully changed. # vgversion -U 1024 -V 2.
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Verify the volume group # vgdisplay vg01 --- Volume groups --VG Name VG Write Access VG Status Max LV Cur LV Open LV Cur Snapshot LV Max PV Cur PV Act PV Max PE per PV VGDA PE Size (Mbytes) Unshare unit size (Kbytes) Total PE Alloc PE Current pre-allocated PE Free PE Total PVG Total Spare PVs Total Spare PVs in use VG Version VG Max Size VG Max Extents Cur Snapshot Capacity Max Snapshot Capacity /dev/vg01 read/write available 2047 0 0 0 2048 1 1 16368 2 4 1024 1021 0 0 1021 0 0 0 2.
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# vgversion -V 2.0 vg01 Performing "vgchange -a y -l -p -s vg01" to collect data Activated volume group. Volume group "vg01" has been successfully activated. Old Volume Group configuration for "/dev/vg01" has been saved in "/etc/lvmconf/vgversion_vg01/vg01_2.2.conf" New Volume Group configuration for "/dev/vg01" has been saved in "/etc/lvmconf/vgversion_vg01/vg01_2.0.conf" Deactivating Volume Group "vg01" Volume group "vg01" has been successfully deactivated.
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vgversion status messages While using the vgversion command you may see status messages similar to the following: A Version 2.x Volume Group with the minor number 0x1000 already exists The minor number is already used by a Version 2.x volume group. The vgversion command selects the first available minor number. While converting a Version 1.0 volume group to a 2.x volume group, vgversion tries to retain the volume group minor number as is.
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Error: The Physical Volume "/dev/disk/disk348" has bad blocks relocated on it. Version 2.x volume groups cannot handle bad blocks on physical volumes. If any physical volumes of a Version 1.0 volume group have relocated bad blocks, vgversion fails the migration. You cannot migrate the volume group to 2.x. Error: The Physical Volume "/dev/disk/disk348 " has the pvkey 512, which is not supported by volume group Version 2.0 The pvkey of a physical volume of a Version 2.
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Removing the Volume Group /dev/vg01 from /etc/lvmtab While migrating a volume group from Version 1.0 to 2.x, vgversion removed the volume group entry from the /etc/lvmtab file and added the entry to /etc/lvmtab_p file. The space required for Volume Group Version 2.1 metadata on Physical Volume /dev/disk/disk14 is 7408 KB, but available free space is 3072 KB. 2 free user extents from the end of the Physical Volume /dev/disk/disk14 will be utilized to accommodate the Volume Group Version 2.1 metadata.
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For more information To learn more about LVM and HP-UX system administration, see the following documents on the HP on the HP Business Support Center at: http://www.hp.