Patent ID: 6950915
Filing Date: 2005-09-27
Classification: G06F,Y10S

Abstract:
1. A method for copying information from a first storage subsystem to a second storage subsystem, the first and second storage subsystems being provided in a data storage system, the method comprising: determining whether or not a first command received at a first storage subsystem from one of a plurality of first hosts is an update command or control command, the first storage subsystem being coupled to a plurality of first hosts, the first subsystem including a storage unit, a storage controller, first communication interfaces coupled to the plurality of first hosts, a second communication interface coupled to the second storage subsystem; writing data associated with the first command to a first cache memory of the first storage subsystem if the first command is determined to be an update command, the data written to the first cache memory including a first data block; executing the first command at the first storage subsystem if the first command is determined to be a control command, where first attribute information is obtained by executing the first command; transmitting the first data block from the first storage subsystem to the second storage subsystem, the second storage subsystem being associated with a second host; storing the first attribute information associated with the first control command to a first shared memory of the first storage subsystem; and transmitting the first attribute information from the first storage subsystem to the second storage subsystem without direct involvement from the first hosts, wherein the first and second hosts are coupled to each other via a first communication link to exchange information therebetween, and the first and the second storage subsystems are coupled to each other via a second communication link that is different from the first communication link, the second communication link being used to transmit the first data block and the first attribute information from the first storage subsystem to the second storage subsystem.