Patent ID: 7082506

Claim:
A remote copy control method, for a storage sub-system which includes a control memory for storing control data, a cache memory for temporarily storing data, a micro processor for controlling said control memory and said cache memory, N transmission destinations for synchronously receiving said data from said micro processor, and M transmission destinations for asynchronously receiving said data from said microprocessor, said remote copy control method comprising: a first step of storing, in said control memory, transfer states/bit maps corresponding to said N+M data destinations; a second step of another storage sub-system, which includes a transfer state/bit map that corresponds to one of said transfer states/bit maps, issuing to a storage sub-system that does not directly perform data transmission a command for transmitting an inquiry for a data update process state; and a third step of, upon receiving a response to said command at said second step, updating said transfer states/bit maps.