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About disk group configuration backup

Disk group configuration backup and restoration allows you to backup and restore all configuration data for Veritas Volume Manager (VxVM) disk groups, and for VxVM objects such as volumes that are configured within the disk groups. Using this feature, you can recover from corruption of a disk group's configuration that is stored as metadata in the private region of a VM disk. After the disk group configuration has been restored, and the volume enabled, the user data in the public region is available again without the need to restore this from backup media.

Warning: The backup and restore utilities act only on VxVM configuration data. They do not back up or restore any user or application data that is contained within volumes or other VxVM objects. If you use vxdiskunsetup and vxdisksetup on a disk, and specify attributes that differ from those in the configuration backup, this may corrupt the public region and any data that it contains.

The vxconfigbackupd daemon monitors changes to the VxVM configuration and automatically records any configuration changes that occur. Two utilities, vxconfigbackup and vxconfigrestore, are provided for backing up and restoring a VxVM configuration for a disk group.

When importing a disk group, any of the following errors indicate that the disk group configuration and/or disk private region headers have become corrupted:

VxVM vxconfigd ERROR V-5-1-569 Disk group group,Disk disk:Cannot auto-import group: reason

The reason for the error is usually one of the following:

Configuration records are inconsistent

Disk group has no valid configuration copies

Duplicate record in configuration

Errors in some configuration copies

Format error in configuration copy

Invalid block number

Invalid magic number

If VxVM cannot update a disk group's configuration because of disk errors, it disables the disk group and displays the following error:

VxVM vxconfigd ERROR V-5-1-123 Disk group group: Disabled by errors

If such errors occur, you can restore the disk group configuration from a backup after you have corrected any underlying problem such as failed or disconnected hardware.

Configuration data from a backup allows you to reinstall the private region headers of VxVM disks in a disk group whose headers have become damaged, to recreate a corrupted disk group configuration, or to recreate a disk group and the VxVM objects within it. You can also use the configuration data to recreate a disk group on another system if the original system is not available.

  Note   Restoration of a disk group configuration requires that the same physical disks are used as were configured in the disk group when the backup was taken.

See "Backing up a disk group configuration" on page 70.

See "Restoring a disk group configuration" on page 71.