A system and method for managing data updates by cascading those updates through a virtual copy hierarchy from parent copies to child copies are provided. Virtual copies are created and managed through the use of an instant copy mechanism. Metadata subsets manage both the original data and the copies...http://www.google.de/patents/US6996682?utm_source=gb-gplus-sharePatent US6996682 - System and method for cascading data updates through a virtual copy hierarchy
