When local magnetic disks are not automatically identified as HDD devices by ESXi hosts, you can manually mark them as local HDD devices.
If you marked a magnetic disk as a flash device, you can change the disk type of the device by marking it as a magnetic disk.
Prerequisites
- Verify that the magnetic disk is local to your host.
- Verify that the magnetic disk is not in use and is empty.
- Verify that the virtual machines accessing the device are powered off.