HOST SYSTEM FOR REMOTE CONTROL OF MASS STORAGE VOLUMES USING CASCADING COMMANDS

A host system for remote control of mass storage volumes using cascading commands which collect information about linked remote volumes located in physically separate sites so other cascading commands can be issued to effect changes in linked remote volumes. A host computer program issues the cascading commands which ask the locally communicating mass storage system to return information which can be used to identify one or more levels of remote mass storage systems in a stream of remote mass storage systems. Once a mass storage system at a given level has been identified, commands can be sent by the host through the locally communicating mass storage system to cause actions to occur at the identified remote level, whether or not there are multiple intervening levels of remote mass storage systems. In one embodiment, a host computer can query, establish, split, re-establish, copy, restore, reverse split, differentially split and reverse differentially split business continuance volumes at any level in a stream of local and remote mass storage system sites.