Patent ID: 7269611

Claim:
A storage system comprising: a plurality of sites each comprising a plurality of host computers and a respective storage device providing logical volumes to these host computers, each of said host computers being assigned with access to at least one of said logical volumes; an inter-site network that communicably connects the sites to each other; a synchronizing part that synchronizes data stored in said logical volumes of said respective storage devices in the sites via said inter-site network; a reference managing part which manages reference designating information that designates a logical volume holding the most recent data as a reference volume if a synchronization trouble occurs in the synchronization processing performed by the synchronizing part, said synchronization trouble affecting the normal performance of the synchronization processing performed by the synchronizing part; and a control part that controls failover processing among said host computers on the basis of said reference designating information, wherein if one of said host computers assigned with access to said reference volume fails during said synchronization trouble and prior to a recovery from said synchronization trouble, another one of said host computers assigned with access to said reference volume performs failover processing to take over after said failed host computer using said reference volume, while preventing another one or more of said host computers not assigned with access to said reference volume from performing failover processing to take over after said filed host computer.