Patent ID: 7565570
Filing Date: 2009-07-21
Classification: G06F

Abstract:
1. A disk array device comprising: a first control unit connected to a host system via a first path through which data is transmitted and received; a second control unit connected to said host system via a second path through which data is transmitted and received upon a failure; a memory that stores control information, wherein the control information comprises a flag, which indicates whether the time used in transmitting and receiving data to and from the host system is less than a first threshold value or whether the time used in transmitting and receiving data to and from the host system is greater than the first threshold value; and a storage apparatus that stores data transmitted from said host system, wherein said first control unit controls the transmission and reception of data between said host system and said storage apparatus conducted via said first path, and stores the control information used in the communication with said host system in said memory, and wherein said second control unit comprises: a determination unit that determines whether a failure occurred in the communication between said second control unit and said host system based on a response to said command.