An agent module of a host directs I/O requests accessing a first disk of a first storage array to access a second disk of a second storage array. The agent module obtains a disk identifier of a first disk in the first storage array and a disk identifier of a second disk in the second storage array to record a mapping relationship between them. The agent module further reports virtual path information for a virtual path between the agent module and a multipath module of the host to the multipath module. The agent module sends the disk identifier of the first disk via the virtual path after receiving a disk identifier query request for querying the identifier of the second disk. Thus, the agent module can send an I/O request for accessing the first disk to the second storage array to access the second disk.