Patent ID: 8996908
Filing Date: 2015-03-31
Classification: G06F

Abstract:
1. An information system comprising: a first storage system configured to provide a first storage area; a second storage system configured to provide a second storage area paired with the first storage area; and a first host system and a second host system coupled to the first and second storage systems and configured to transmit write requests, wherein (A) in a first system status that is in a normal status, the first and second storage systems perform a first remote data mirroring process in which the first storage area is a source, and the second storage area is a target, a first path connecting the first host system to the first storage area is in a status representing that the first path has a higher priority than a second path connecting the first host system to the second storage area, and a third path connecting the second host system to the first storage area is in a status representing that the third path has a higher priority than a fourth path connecting the second host system to the second storage area, (B) in a second system status that is brought about when the first storage system fails a process according to the write request received from the first or second host system in the first system status, each of the first and third paths is in a status representing inhibition of transmission of the write request using the path, and the first and second storage systems stop the first remote data mirroring process, (C) in a third system status that represents recovery in the second system status to a situation where the first and second host systems are permitted to transmit the write requests to the first storage system, the first and second storage systems perform a second remote data mirroring process in which the second storage area is a source, and the first storage area is a target, the first path is in a status representing that the priority of the first path is lower than the priority of the second path, and the third path is in a status representing that the priority of the third path is lower than the priority of the fourth path, (D) upon transition to a status representing that the priority of the first path is higher than the priority of the second path in the third system status, (1) the first host system transmits the write request to the first storage system using the first path, (2) the first storage system receives the write request from the first host system, detects that the first storage area which is a write destination according to the received write request is the target in the second remote data mirroring process, transmits a stop notification to stop the second remote data mirroring process to the second storage system, and stops the second remote data mirroring process, (3) the second storage system receives the stop notification, and changes control so that a write request specifying the second storage area as a write destination fails, and (4) the second host system transmits the write request specifying the second storage area as the write destination to the second storage system using the fourth path, and transmits the write request using the third path which is in a status representing that the priority of the third path is lower than the priority of the fourth path when the write request fails.