cli_chvg command

Purpose

Syntax

cli_chvg  [ -s Sync { y | n }] [ -L LTGSize ] [ -Q { n | y } ] [ -u ]
          [ -t [factor ] ] [ -M { y | n | s } ] [ -B ] [ -C  ] VolumeGroup

Description

Uses C-SPOC to run the chvg command with the specified parameters and make the updated volume group definition available on all cluster nodes.

Flags

-B

Changes the volume group to Big VG format. This flag can accommodate up to 128 physical volumes and 512 logical volumes. You cannot use this flag if there are any stale physical partitions in the cluster node. To use this flag, you must have enough free partitions available on each physical volume for the VGDA expansion.

Because the VGDA resides on the edge of the disk and it requires contiguous space for expansion, the free partitions are required on the edge of the disk. If those partitions are allocated for application data, they are migrated to other free partitions on the same disk. The rest of the physical partitions are renumbered to reflect the loss of the partitions for VGDA usage. This process changes the mappings of the logical to physical partitions in all the physical volumes in the volume group.

If you saved the mappings of the logical volumes for a potential recovery operation, you can generate the maps again after the completion of the conversion operation. If the backup of the volume group is taken with the map option and if you plan to restore using those maps, the restore operation can fail since the partition number might not exist (due to reduction). It is recommended that you back up your logical volumes before you start the conversion process, and right after the conversion process completes if you use the map option.

Because the VGDA space is increased substantially, every VGDA update operation (creating a logical volume, changing a logical volume, adding a physical volume, and so on) might take considerably more time to run.

-C

Changes the volume group into an enhanced concurrent capable volume group. Changes the volume group from a non-concurrent mode (varied on) to enhanced concurrent mode. This process requires that the volume group is reimported on all other nodes before activation of the enhanced concurrent mode. Changes the volume group from a concurrent mode (varied on) to an enhanced concurrent mode. You can use this flag only in a PowerHA® SystemMirror® cluster, and the cluster must be configured before you activate an enhanced concurrent volume group.

-L LTGSize

Sets the logical track group size to the common max transfer size of the disks when a volume group is varied on. The value of the LTGSize variable must be 0, 128, 256, 512, or 1024. The LTGSize variable must be less than or equal to the maximum transfer size of all disks in the volume group. The default value for the LTGSize variable is 128. If you specify an LTGSize of 0, the varyonvg command sets the logical track group size to the common max transfer size of the disks.

-M

Changes the mirror pool structures for the volume group. The following values are valid:

y

Each logical volume copy that is created in the volume group must be assigned to a mirror pool.

n

Restrictions are not placed on the user of the mirror pool. This option is the default value.

s

Super-strict mirror pools are enforced on the volume group.

Note: Local and remote physical volumes cannot belong to the same mirror pool. A volume group can contain a maximum of three mirror pools. Each mirror pool must contain at least one copy of each logical volume in the volume group.

-Q

Determines whether the volume group is automatically varied off after losing its quorum of physical volumes. The default value is yes. The change takes effect the next time the volume group is activated. The following values are valid:

y

The volume group is automatically varied off after losing its quorum of physical volumes.

n

The volume group is active until it loses all of its physical volumes.

-s Sync

Sets the synchronization characteristics for the volume group that is specified by the VolumeGroup variable. This flag does not affect non-mirrored logical volumes. This flag is not supported for concurrent capable volume groups.

Automatic synchronization is a recovery mechanism that is only attempted after the Logical Volume Manager (LVM) device driver logs LVM_SA_STALEPP in the AIX® operating system error log. A partition that becomes stale through any other path (for example, the mklvcopy command) is not automatically resynced. The following values are valid:

y

Attempts to automatically synchronize stale partitions.

n

Prohibits automatic synchronization of stale partitions. This value is the default setting for a volume group.

-t factor

Changes the limit of the number of physical partitions per physical volume, which is specified by a factor. The factor must be 1 - 16 for 32 physical volumes groups. The factor must be 1 - 64 for 128 physical volume groups.

If you do not specify the factor, it is set to the lowest value such that the number of physical partitions of the largest disk in the volume group is less than the factor value multiplied by 1016.

If you do specify a factor, the maximum number of physical partitions per physical volume for the volume group changes to the factor value multiplied by 1016.

Review the following information when you are determining the value for the factor:

• This flag is ignored for scalable-type volume groups.
• This flag cannot be used if the volume group is varied on in concurrent mode.
• The factor value cannot be changed if there are any stale physical partitions in the volume group.
• The maximum number of physical volumes that are allowed in this volume group is reduced to the value you get when you divide MAXPVS by the factor value (MAXPVS/factor).
• Changing an existing volume group to scalable volume group format, modifies the device subtype (reported by the IOCINFO ioctl() call) for all associated logical volumes to DS_LVZ, regardless of the previous subtype. This change does not alter any behavior of the logical volumes beyond the reported subtype.

-u

Unlocks the volume group. This flag is available if the volume group is left in a locked state by an abnormal termination of another LVM operation (such as the command core dumping or the system crashing). Before you can use this flag, you must verify that the volume group is not being used by another LVM command.

Example

cli_chvg -Q n vg01