The system configuration data of the S2300 controller enclosure is stored on the coffer disks, that is, hard disks in slots 0 to 3. Furthermore, when a power failure occurs to the S2300 storage system, the battery modules provide power for its controller enclosure, and then cache data is flushed on to the coffer disks within two minutes. Therefore, during the deployment, hard disks must be inserted in slots 0 to 3 of the controller enclosure.