Patent ID: 7451285
Filing Date: 2008-11-11
Classification: G06F

Abstract:
1. A computer system comprising: a computer; a first primary storage system, connected to the computer, providing a first virtual storage area to the computer; a second primary storage system connected to the first primary storage system and including a first real storage area; a third primary storage system connected to the second primary storage system and providing a second virtual storage area, wherein the first real storage area of said second primary storage system corresponds to both said first virtual storage area of the first primary storage system and said second virtual storage area of the third primary storage system; a first secondary storage system connected to the first and second primary storage systems through a communication line and including a second storage area; and a management computer connected to the first and second primary storage systems and the computer, wherein the second primary storage system, responsive to a write request of write data to the first virtual storage area of the first primary storage system, received from the computer, stores the write data into the first real storage area; wherein remote copying is conducted between the first real storage area of the second primary storage system and the second storage area of the first secondary storage system, wherein the remote copying is classified into initial copying and regular copying, wherein in the initial copying data is copied from the first real storage area to the second storage area to make contents of the first real storage area equal to contents of the second storage area, and in the regular copying write data received by the first primary storage system from the host computer is transferred to the first secondary storage system to be stored in the second storage area, wherein when conducting the initial copying, the management computer instructs the second primary storage system to copy data stored in the first real storage area into the second storage area through the second virtual storage area, and wherein when conducting the regular copying, the management computer instructs the first primary storage system to copy the write data received from the computer into the second storage area through the first virtual storage area.