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.
- 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.
- Navigate to the vSAN cluster.
- Click the Configure tab.
- Under vSAN, click Disk Management.
- Select the host to view the list of available magnetic disks.
- From the Show drop-down menu at the bottom of the page, select Not in Use.
- Select one or more magnetic disks from the list and click Mark as HDD Disk.
- Click Yes to save.
The Drive Type for the selected magnetic disks appears as HDD.