STORAGE SYSTEM WITH CASCADED COPY TARGETING FUNCTION AND ENHANCED PERFECTIBILITY

PROBLEM TO BE SOLVED: To provide a storage system with a cascaded copy targeting function and enhanced perfectibility. SOLUTION: A storage controller cooperable with a host computer device and a plurality of controlled storage apparatuses comprises: a host write component operable to write a data object to a source data image at one of a plurality of the controlled storage apparatuses; a copy component operable in response to a metadata state to control the copying of the data object to a target data image in a delimited sequence of data images in a cascade at the plurality of controlled storage apparatuses; and a fill-in component operable in response to the detection of an offline condition of a disk containing the target data image to control the substitution of a fill-in disk in place of the disk containing the target data image. COPYRIGHT: (C)2006,JPO&NCIPI