Patent ID: 7725445

Claim:
A storage system, outside of a host computer, coupled to another storage system, the storage system comprising: a plurality of disk drives; a plurality of first replication volumes, provided from areas of said plurality of drives, allocated to a first group, and storing a plurality of replicated data, corresponding to a plurality of data to be stored in a plurality of first volumes of the another storage system, wherein a consistency of the plurality of replicated data of the plurality of first replication volumes is maintained; a first journal volume provided from areas of said plurality of drives and storing a plurality of journal data, received from the another storage system and related to the first group, the plurality of journal data stored in the first journal volume used to update a plurality of replicated data to be stored in at least one of the plurality of first replication volumes; a plurality of second replication volumes, provided from areas of said plurality of drives, allocated to a second group, and storing replicated data, corresponding to data to be stored in a plurality of second volumes of the another storage system, wherein a consistency of the plurality of replicated data of the plurality of second replication volumes is maintained; and a second journal volume provided from areas of said plurality of drives and storing a plurality of journal data, received from the another storage system and related to the second group, the plurality of journal data stored in the second journal volume used to update a plurality of replicated data to be stored in at least one of the plurality of second replication volumes, wherein an oldest journal data stored in the first journal volume is read from the first journal volume, wherein a replicated data corresponding to the oldest journal data stored in the first journal volume is written to one of the plurality of first replication volumes, wherein an oldest journal data stored in the second journal volume is read from the second journal volume, and wherein a replicated data corresponding to the oldest journal data stored in the second journal volume is written to one of the plurality of second replication volumes.