A method, apparatus and computer program product for performing an instant
copy of data are provided to support dynamically changeable virtual
mapping schemes in a data processing system. The present invention
separates processing of data unit requirements from the selection of which
storage subsystems to use for storage by using a storage methodologies
inventory. Various instant copy mechanisms are provided for copying data
upon receiving a write operation to either original or copy data. The
instant copy mechanisms may be selected based on the type of mapping
originally used to store the data that is to be copied. Determining the
mapping of the data may include parsing extents of the data into sets
based on types of mapping used to map extents. The mapping of the data may
be one of load point and offset, and a full pointer mapping.
