Patent ID: 7945753

Claim:
A computer system comprising: a first storage system coupled to a primary host computer; a second storage system coupled to a secondary host computer; a third storage system; wherein said first storage system is coupled to said second storage system and said third storage system, and said second storage system is coupled to said third storage system, wherein, when a state of said primary host computer is in an active state, a data sent from the primary host computer to said first storage system is copied through a first copy route which includes a route from said first storage system to said second storage system and a route from said second storage system to said third storage system, wherein, if a failure occurs in said primary host computer and a state of said second host computer is to be in an active state, a data sent from said secondary host computer to said second storage system is copied through a second copy route which includes a route from said second storage system to said first storage system and a route from said first storage system to said third storage system.