CIM_AggregatePSExtent defines the number of addressable logical blocks on a single storage device, excluding any logical ...

CIM_AggregatePSExtent defines the number of addressable logical blocks on a single storage device, excluding any logical blocks mapped as check data. These logical blocks are contained within a single volume set (if volume sets are defined). This is an alternative grouping for CIM_ProtectedSpaceExtent, when only summary information is needed or when automatic configuration is used. Automatic configuration can result in thousands of CIM_ProtectedSpaceExtent being defined. There is no value in modeling the individual extents.  So, the CIM_AggregatePSExtent object was defined.