Patent ID: 8443153

Claim:
A method comprising: in a data storage system, defining a plurality of distinct storage entity types, each of the storage entity types having different characteristics, the plurality of distinct storage entity types including a volume type, a region type, a logical extent type, a slab type and a block type; in the data storage system, defining a plurality of regions of the region type to contain data, the plurality of regions including a plurality of logical extents of the logical extent type, wherein allocated to each said logical extent is at least a portion of one or more slabs of the slab type allocated to a region that includes said logical extent, each said slab defined as a set of blocks of the block type in one or more physical storage devices; in the data storage system, maintaining, by a volume layer, a plurality of volumes of the volume type 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 volume layer; and making a block sharing or duplication decision for a block of physical storage, based on a service level objective (SLO), wherein making the block sharing or duplication decision for the block of physical storage includes determining whether to share the block between two or more logical extents, based on an SLO applicable to the block.