A disaster-tolerant data backup and remote copy system which is implemented as a controller-based replication of one or more LUNs (logical units) between two remotely separated pairs of array controllers connected by redundant links. The system provides a method for allowing a large number of commands...http://www.google.com/patents/US20040044865?utm_source=gb-gplus-sharePatent US20040044865 - Method for transaction command ordering in a remote data replication system
