Patent ID: 8332361

Claim:
A storage system comprising: a first storage apparatus coupled to a host computer, the first storage apparatus including a plurality of first disk drives for storing data and a first controller for controlling the storing of the data in the plurality of first disk drives; a second storage apparatus coupled to the first storage apparatus, the second storage apparatus including a plurality of second disk drives for storing data and a second controller for controlling the storing of the data in the plurality of second disk drives; and a third storage apparatus coupled to the first storage apparatus, the third storage apparatus including a plurality of third disk drives for storing data and a third controller for controlling the storing of the data in the plurality of third disk drives; wherein the first controller is configured to: store data received from the host computer in a first volume of data storage created from a portion of the first disk drives; generate a data set that comprises the data stored in the first volume and an update number that expresses an update order of the data stored in the first volume; store the generated data set in a first journal volume of data storage created from another portion of the first disk drives; and transmit one or more generated data sets to the second storage apparatus and to the third storage apparatus; wherein the second controller is configured to: store the one or more generated data sets transmitted from the first storage apparatus in a second journal volume created from a portion of the second disk drives; and store data related to the one or more data sets stored in the second journal volume in a second volume created from another portion of the second disk drives according to an update number included in the one or more generated data sets; and wherein the third controller is configured to: store the one or more generated data sets transmitted from the first storage apparatus in a third journal volume created from a portion of the third disk drives; and store data related to the one or more data sets stored in the third journal volume in a third volume created from another portion of the third disk drives according to another update number included in the one or more generated data sets; wherein, in response to a failure that occurs in the first storage apparatus, the second controller is operable to transmit the one or more data sets stored in the second journal volume such that the third controller stores one or more data sets, comprising data not stored in the third volume, related to the one or more data sets, transmitted from the second storage apparatus in the third volume, according to the update number included in the one or more data sets stored in the second volume.