Various embodiments set forth techniques for managing metadata for a vblock include dynamically normalizing and denormalizing vblock metadata associated with an extent. Vblock metadata associated with an extent is normalized when the extent is migrated to a different extent group by having the vblock metadata to a mapping between the extent identifier and an extent group identifier in a metadata map separate from the vblock metadata. Vblock metadata associated with an extent is denormalized whenever the number of vblock metadata associated with an extent drops below a threshold. Vblock metadata is denormalized by updating the vblock metadata to include a mapping to an extent group, based on a mapping of the extent to the extent group in a separate metadata map, and then removing the mapping in the separate metadata map.