A storage administrator may maintain location information in separate layers. A data storage system may identify the location of particular data by identifying the virtual location of data, such as the logical extent to which the data belongs. Object stores may maintain mappings of virtual locations to physical locations, such as mappings of extent identifiers to virtual storage objects and mappings of virtual storage objects to storage unit locations. When particular data is relocated to a new location, a storage administrator may update mappings used to translate virtual locations to physical locations, such as an extent-object mapping or an object-storage unit mapping. References to the virtual locations, such as references to logical extent identifiers, may not be updated in response to the relocation of data.