vgcfgrestore

vgcfgrestore [OPTIONS] VolumeGroupName [-f | --file FileName]

-f, --file <FileName>
    Specifies the path to the metadata archive file to be restored from. If omitted, vgcfgrestore searches the standard archive locations for the most recent backup for the given VG.

-l, --list-history
    Lists the metadata history of the specified Volume Group, showing available archive versions.

-t, --test
    Performs a dry run; vgcfgrestore will simulate the restoration process and report potential outcomes without making any actual changes to the system. This is highly recommended for safety.

-F, --force
    Forces the restoration even if inconsistencies or warnings are detected, such as when the metadata to be restored differs significantly from the current metadata. Use with extreme caution as it can lead to data loss.

--uuid <UUID>
    Restores the Volume Group using a specific UUID from its history. This is an advanced option typically used when multiple backups for a VG exist and a particular state needs to be restored.

-v, --verbose
    Provides more detailed output during the restoration process, showing steps taken and potential issues.

-y, --yes
    Assumes 'yes' to all prompts, allowing the command to proceed without requiring user confirmation.

-h, --help
    Displays a help message with usage information and available options.

-V, --version
    Shows the version of the vgcfgrestore command.

The vgcfgrestore command is a vital utility within the Logical Volume Manager (LVM) suite in Linux, designed to restore the metadata configuration of a Volume Group (VG) from a previously saved backup. LVM metadata stores crucial information about the structure of your logical volumes (LVs), physical volumes (PVs), and the volume group itself, including their sizes, names, and interconnections.

This command is primarily used in disaster recovery scenarios, such as when VG metadata becomes corrupted, is accidentally deleted, or if a VG needs to be reassembled on different physical disks. LVM automatically saves metadata backups in /etc/lvm/archive before most significant configuration changes, providing a safety net. Users can also manually create backups using vgcfgbackup.

When vgcfgrestore is executed, it reads the metadata from a specified archive file and attempts to apply it to the corresponding Volume Group. It's crucial that the underlying physical volumes (PVs) that comprised the VG at the time of the backup are present and accessible, as the command only restores metadata, not the data on the logical volumes themselves. Mismatched PV UUIDs or missing PVs can prevent a successful restore.

While powerful, vgcfgrestore must be used with extreme caution. Incorrect usage or restoring an unsuitable backup can lead to irreversible data loss or make your logical volumes inaccessible. It's often recommended to use the --test option first to preview the changes before committing them with --force.

• Data Loss Risk: Incorrectly using vgcfgrestore, especially with the --force option, can lead to irreversible data loss or render your logical volumes inaccessible. Always back up critical data before attempting a restore.
• Metadata Only: This command restores only the LVM metadata; it does not restore the actual data stored on your logical volumes. Your data remains untouched but might become inaccessible if the metadata is restored incorrectly.
• Physical Volume Consistency: For a successful restore, the underlying physical volumes (PVs) that were part of the Volume Group at the time the backup was created must be present, accessible, and their UUIDs must match. If PVs have been changed or replaced, recovery can be more complex.
• LVM2 Format: vgcfgrestore is part of the LVM2 suite and expects LVM2 metadata format. It cannot restore LVM1 metadata.
• Read-Only Volume Groups: A Volume Group must not be active or read-only when attempting to restore its configuration. You may need to deactivate it first (e.g., using vgchange -an <VGName>).

LVM automatically creates metadata backups in the /etc/lvm/archive directory (and sometimes /etc/lvm/backup) whenever significant changes are made to a Volume Group, such as creating or deleting logical volumes, or resizing them. These automatic backups are timestamped and are the primary source for vgcfgrestore if no specific file is provided.

The metadata archives are plain text files that describe the complete configuration of the Volume Group, including all its physical volumes, logical volumes, and their properties. While it's possible to inspect these files manually, it's generally not recommended to edit them directly due to the complexity and risk of corruption.

vgcfgrestore is an integral part of the LVM2 (Logical Volume Manager version 2) suite, which became the standard LVM implementation in Linux kernels starting around 2.6. It evolved from the earlier LVM1 to provide more robust, flexible, and scalable storage management capabilities. The ability to restore metadata from backups was a critical feature designed into LVM2 from its inception, recognizing the importance of metadata integrity for storage reliability and disaster recovery. Its development has focused on enhancing reliability and providing finer control over restoration processes.

vgcfgbackup(8), lvm(8), vgchange(8), vgdisplay(8), lvcreate(8), lvremove(8), pvcreate(8), pvremove(8)