SAS cable is not inserted well, reinsert SAS cable, and Raid card can recognize hard disk.
Server safely power off, open shelf, plug and reinsert SAS cable connected to Raid card.
If Raid card configuration interface cannot recognize hard disk information, please check according to steps like below:
1. Plug and reinsert SAS cable of Raid card.
2. Replace new SAS cable.
3. Replace new Raid card.