Patent ID: 8555022

Claim:
A method comprising: in a data storage system, defining a plurality of regions to contain data, the plurality of regions including a plurality logical extents; in the data storage system, defining a first slab as a portion of a foreign logical unit (LUN), and allocating at least a portion of the first slab to a first logical extent of the plurality of logical extents, the first logical extent being included within a first region of the plurality of regions, wherein a device associated with the foreign LUN is not manufactured by a manufacturer of the data storage system and the device associated with the foreign LUN is not specifically designed for use with the data storage system; storing at least one write-back change to the foreign LUN in a native storage separate from the foreign LUN; and in the data storage system, maintaining a plurality of volumes as logical containers of data, each of the volumes including one or more of the logical extents from one or more of the regions, wherein layouts of the logical extents within the regions are not visible to the plurality of volumes.