This disk array device includes 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 the host system via a second path
through which data is transmitted and received upon a failure, a memory
storing control information, and a storage apparatus storing data
transmitted from the host system; wherein the first control unit controls
the transmission and reception of data between the host system and the
storage apparatus conducted via the first path, and stores the control
information used in the communication with the host system in the memory;
and wherein the second control unit has a transmission unit for
transmitting a command to the host system via the second path based on
the control information used in the communication stored in the memory,
and a determination unit for determining whether a failure occurred in
the communication between the second control unit and the host system
based on a response to the command.