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.
The vxconfigbackupd daemon monitors changes to the VxVM configuration and automatically records any configuration changes that occur, probably after an hour. 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 in the vxconfigd log indicates 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.