When you configure vSAN or set up a virtual flash resource, your storage environment must include local flash devices. However, ESXi might not recognize certain storage devices as flash devices when their vendors do not support automatic flash device detection. In other cases, certain devices might not be detected as local, and ESXi marks them as remote. When devices are not recognized as the local flash devices, they are excluded from the list of devices offered for vSAN or virtual flash resource. Marking these devices as local flash makes them available for vSAN and virtual flash resource.

Mark Storage Devices as Flash

If ESXi does not recognize its devices as flash, mark them as flash devices.

ESXi does not recognize certain devices as flash when their vendors do not support automatic flash disk detection. The Drive Type column for the devices shows HDD as their type.
Caution: Marking the HDD devices as flash might deteriorate the performance of datastores and services that use them. Mark the devices only if you are certain that they are flash devices.

Prerequisites

Verify that the device is not in use.

Procedure

  1. In the vSphere Client, navigate to the ESXi host.
  2. Click the Configure tab.
  3. Under Storage, click Storage Devices.
  4. From the list of storage devices, select one or several HDD devices and click the Mark as Flash Disk (Mark as flash disk.) icon.
  5. Click Yes to save your changes.

Results

The type of the devices changes to flash.

What to do next

If the flash device that you mark is shared among multiple hosts, make sure that you mark the device from all hosts that share the device.

Mark Storage Devices as Local

ESXi enables you to mark devices as local. This action is useful in cases when ESXi is unable to determine whether certain devices are local.

Prerequisites

  • Make sure that the device is not shared.
  • Power off virtual machines that reside on the device and unmount an associated datastore.

Procedure

  1. In the vSphere Client, navigate to the ESXi host.
  2. Click the Configure tab.
  3. Under Storage, click Storage Devices.
  4. From the list of storage devices, select one or several remote devices and click the Mark as Local icon.
  5. Click Yes to save your changes.