Patent ID: 8468316

Claim:
A backup control apparatus for periodic data backup in a virtualized storage system having a point-in-time copy function operable to copy first data into a cascade and comprising: a storage targeting component for selecting a first target virtual disk for one of a full copy or an incremental copy of the first data; a periodic backup component for triggering a periodic point-in-time copy of the first data to a virtual disk in the cascade; a testing component for testing a status of the full copy, the incremental copy and the periodic point-in-time copy; and a cascade splitting component responsive to the status for splitting the cascade to remove a dependency relationship of at least one of the full copy, the incremental copy and the periodic point-in-time copy on the first data, and to insert a second target virtual disk between the first data and the full copy, the incremental copy, and the periodic point-in-time copy, wherein: prior to the splitting of the cascade, the first data is located at a first position in the cascade, and the full copy, the incremental copy, and the periodic point-in-time copy are arranged in and make up a first configuration of components located in a second position downstream from the first position, during the splitting of the cascade, the second tar et virtual disk is inserted immediately adjacent the first data between the first position and the second position, and as a result of the splitting of the cascade the first data remains at the first position, the second target virtual disk is re-positioned at a location not immediately adjacent the first data, the full copy, the incremental copy, and the periodic point-in-time copy are rearranged into a second configuration that is different from the first configuration of components, and the first tar et virtual disk is isolated from the cascade and attached to a new virtual disk.