vgconvert

vgconvert [-s|--setversion Version] [-M|--metadatacopies Number] [COMMON_OPTIONS] VolumeGroupName...

-s version, --setversion version
    Sets the metadata format version (e.g., '1' for LVM1, '2' for LVM2).

-M number, --metadatacopies number
    Specifies the number of metadata copies to store on each Physical Volume.

-f, --force
    Force the operation, overriding certain checks. Use with caution.

-y, --yes
    Assume 'yes' to all questions; bypasses interactive prompts.

-v, --verbose
    Enable verbose output, showing detailed runtime information.

-h, --help
    Display a help message and exit.

-V, --version
    Show program version information and exit.

VolumeGroupName...
    One or more names of the Volume Groups to be converted.

The `vgconvert` command in Linux LVM (Logical Volume Manager) is used to change the metadata format of an existing volume group. Its primary historical use was to migrate volume groups from the older LVM1 metadata format to the more advanced and feature-rich LVM2 format. While LVM2 is now the default and widely adopted standard, `vgconvert` remains useful for ensuring compatibility or adjusting metadata properties like the number of metadata copies stored on physical volumes. For a successful conversion, the target volume group must be inactive, meaning no logical volumes within it are in use. This command is a critical tool for LVM administrators managing evolving storage infrastructures or integrating older LVM setups with modern systems. It allows for an in-place upgrade of the metadata structure, unlocking new features and improving resilience.

The target volume group must be inactive before running `vgconvert` (e.g., using `vgchange -an VolumeGroupName`).
Converting to a newer LVM format (e.g., LVM2) might render the volume group inaccessible on older systems running LVM1-only kernels or utilities.
Always back up LVM metadata using `vgcfgbackup` before performing any metadata conversions or modifications.

For `vgconvert` to operate successfully, the target volume group must be in an inactive state. This ensures that no logical volumes within the group are in use or mounted, preventing data corruption during the metadata conversion process. Use `vgchange -an VolumeGroupName` to deactivate it prior to conversion and `vgchange -ay VolumeGroupName` to reactivate it afterward.

Before performing any potentially disruptive operations like metadata conversions, it is highly recommended to back up your LVM metadata. The `vgcfgbackup` command can be used for this purpose. In case of unforeseen issues, metadata can be restored using `vgcfgrestore`, mitigating data loss.

`vgconvert` gained prominence during the transition from the original LVM (often called LVM1) to LVM2. LVM2 introduced significant improvements in scalability, flexibility, and features. This command was crucial for administrators to update their existing LVM1 volume groups to the LVM2 metadata format, enabling them to leverage the new capabilities without recreating their storage infrastructure. While new LVM deployments now default to LVM2, `vgconvert` remains an essential tool for maintaining and ensuring compatibility of legacy LVM setups.

vgchange(8), vgdisplay(8), vgcreate(8), lvm(8), vgcfgbackup(8)