Data Management attributes can be associated with any individual file. There are opaque and nonopaque attributes. An opaque attribute has a unique name, and a byte string value which is not interpreted by the DMAPI implementation. Nonopaque attributes, such as managed regions and event lists, are used internally by the DMAPI implementation.
DM attributes are persistent. They are kept in a hidden file in the file system.
GPFS provides two "quick access" single-bit opaque DM attributes for each file, stored directly in the i-node. These attributes are accessible through regular DMAPI functions, by specifying the reserved attribute names _GPFSQA1 and _GPFSQA2 (where _GPF is a reserved prefix). The attribute data must be a single byte with contents 0 or 1.