Patent ID: 8176010

Claim:
A remote copy system comprising: a plurality of host computers; a plurality of first storage systems, each comprising a first control section to be coupled to at least one host computer of the plurality of host computers, at least one first logical volume for storing data received from the at least one host computer, and a first storage area for storing data; and a plurality of second storage systems, each coupled to corresponding ones of the plurality of first storage systems and comprising a second control section, at least one second logical volume for storing a replica of data stored in the first logical volume of a corresponding one of the plurality of first storage systems, and a second storage area for storing data received from the corresponding one of the plurality of first storage systems, wherein the first control sections of the plurality of first storage systems receive a plurality of write requests from the host computer and store a plurality of write data, which relate to the plurality of write requests, in the first storage areas of the plurality of first storage systems, wherein the host computer: (A) sends instructions for deferment of write request processing to all of the first control sections of the plurality of the first storage system, (B) sends a marker instruction to all of the first control sections after receiving a completion report of the deferment from all of the first control sections, (C) sends instructions for release of the deferment of the write request processing to all of the first control sections after receiving a completion report of the marker instruction from all of the first control sections, and repeats the steps of (A), (B), and (C), by incrementing the marker number included in the marker instruction each time the marker instruction is sent, wherein each of the first control sections transfer the plurality of write data associated with the marker, which is included in the latest marker instruction at the time when it is received, to the corresponding one of the second storage systems, wherein at least one host computer determines which marker is made at the earliest time among the markers received by all of the second storage systems and instructs all of the second control sections to store the transferred plurality of write data that is previous to the determined marker, and wherein the each of the second control sections stores the data transferred from the first control section in the corresponding second storage area and restores the data to the second logical volume.