Disk state detection and acquisition method, controller, expander, and control system

The invention discloses a disk state detection and acquisition method, a controller, an expander, and a control system. The expander directly issues a disk state detection request to a disk to be detected; each disk to be detected feeds a detection result back to the expander according to the disk state detection request; and the expander feeds the detection result back to the controller. When disk state detection is performed, the expander directly connected to the disk initiates the disk state detection request; compared with the conventional detection flows initiated by the controller, the disk state detection flow is direct, rapid and efficient; the controller can acquire the corresponding state detection result form a limited expander without issuing the state detection request to each disk, and then the amount of message interaction between the controller and the expander can be greatly reduced; and a link between the controller and the expander will not be occupied in long time, the access efficiency o