Patent ID: 7185157
Filing Date: 2007-02-27
Classification: G06F

Abstract:
1. A method for copying data, comprising: receiving, from a host, a request including an indicator at a first storage control unit having a first set of volumes, wherein the first storage control unit is coupled via a link to a second storage control unit having a second set of volumes that are peer-to-peer copies of the first set of volumes, and wherein the second storage control unit does not have an active link for receiving commands from a device other than the first storage control unit; determining, by processing the indicator included in the request, at the first storage control unit, whether to transmit a command from the first storage control unit to the second storage control unit to generate a copy of the second set of volumes to a third set of volumes at the second storage control unit; transmitting the command, via the link, from the first storage control unit to the second storage control unit, in response to determining by processing the indicator that the command is to be transmitted, to the second storage control unit; copying, at the second storage control unit, the second set of volumes to the third set of volumes, in response to receiving the transmitted command at the second storage control unit from the first storage control unit; and performing operations at the first storage control unit, and not transmitting the command from the first storage control unit to the second storage control unit to generate a copy of the second set of volumes to the third set of volumes at the second storage control unit, in response to determining by processing the indicator that the command is not to be transmitted, to the second storage control unit.