The purpose of dmraid is to arbitrate between the ATARAID on-disk metadata and the device-mapper need to name mapped devices and define mapping tables for them. Because the ATARAID metadata is vendor specific and the respective formats therefore all differ, an internal metadata format abtraction is necessary to translate into and derive the mapped device names and mapping tables content from. The ‘translators’ between the vendor formats and the internal format are called ‘metadata format handlers.’ One of them is needed for anygiven format supported by dmraid.
