Fixing volume group errors

Use these methods to fix volume group errors.

If the importvg command is not working correctly, try refreshing the device configuration database.

Overriding a vary-on failure

Attention: Overriding a vary-on failure is an unusual operation; check all other possible problem sources such as hardware, cables, adapters, and power sources before proceeding. Overriding a quorum failure during a vary-on process is used only in an emergency and only as a last resort (for example, to salvage data from a failing disk). Data integrity cannot be guaranteed for management data contained in the chosen copies of the VGDA and the VGSA when a quorum failure is overridden.

When you choose to forcibly vary-on a volume group by overriding the absence of a quorum, the PV STATE of all physical volumes that are missing during this vary-on process will be changed to removed. This means that all the VGDA and VGSA copies are removed from these physical volumes. After this is done, these physical volumes will no longer take part in quorum checking, nor are they allowed to become active within the volume group until you return them to the volume group. The varyonvg -f flag (used to override quorum loss) is ignored if the volume group has not lost quorum.

Under one or more of the following conditions, you might want to override the vary-on failure so that the data on the available disks in the volume group can be accessed:

Unavailable physical volumes appear permanently damaged.
You can confirm that at least one of the presently accessible physical volumes (which must also contain a good VGDA and VGSA copy) was online when the volume group was last varied on. Unconfigure and power off the missing physical volumes until they can be diagnosed and repaired.

Use the following procedure to avoid losing quorum when one disk is missing or might soon fail and requires repair:

To temporarily remove the volume from the volume group, type:
```
chpv -vr PVname
```
When this command completes, the physical volume PVname is no longer factored in quorum checking. However, in a two-disk volume group, this command fails if you try the chpv command on the disk that contains the two VGDA/VGSAs. The command does not allow you to cause quorum to be lost.
If you need to remove the disk for repair, power off the system, and remove the disk. (For instructions, see Troubleshooting disk drive problems.) After fixing the disk and returning the disk to the system, continue with the next step.
To make the disk available again to the volume group for quorum checking, type:
```
chpv -v a PVname
```
Note: The chpv command is used only for quorum-checking alteration. The data that resides on the disk is still there and must be moved or copied to other disks if the disk is not to be returned to the system.

VGDA warnings

In some instances, the user experiences a problem adding a new disk to an existing volume group or in creating of a new volume group. The message provided by LVM is:

0516-1163 extendvg: VGname already has maximum physical volumes.  With the maximum
number of physical partitions per physical volume being LIMIT, the maximum
number of physical volumes for volume group VGname is MaxDisks.

Where:

VGname: Is the name of the volume group.
LIMIT: Is 1016 or a multiple of 1016.
MaxDisks: Is the maximum number of disks in a volume group. For example, if there are 1016 physical partitions (PPs) per disk, then MaxDisk is 32; if there are 2032, then MaxDisk is 16.

You can modify the image.data file and then use alternate disk installation, or restore the system using the mksysb command to re-create the volume group as a big volume group. For more information, see the Installation and migration.

On older AIX® versions when the limit was smaller than 32 disks, the exception to this description of the maximum VGDA was the rootvg. To provide users with more free disk space, when rootvg was created, the mkvg -d command used the number of disks selected in the installation menu as the reference number. This -d number is 7 for one disk and one more for each additional disk selected. For example, if two disks are selected, the number is 8 and if three disks are selected, the number is 9, and so on.