You can set up a virtual flash resource or add capacity to existing virtual flash resource.

To set up a virtual flash resource, you use local flash devices connected to your host. To increase the capacity of your virtual flash resource, you can add more devices, up to the maximum number indicated in the Configuration Maximums documentation. An individual flash device must be exclusively allocated to the virtual flash resource. No other vSphere service, such as vSAN or VMFS, can share the device with the virtual flash resource.


  1. In the vSphere Web Client, navigate to the host.
  2. Click the Configure tab.
  3. Under Virtual Flash, select Virtual Flash Resource Management and click Add Capacity.
  4. From the list of available flash devices, select one or more devices to use for the virtual flash resource and click OK.
    Under certain circumstances, you might not be able to see flash devices on the list. For more information, see the Troubleshooting Flash Devices section in the vSphere Troubleshooting documentation.


The virtual flash resource is created. The Device Backing area lists all devices that you use for the virtual flash resource.

What to do next

You can use the virtual flash resource for cache configuration on the host and Flash Read Cache configuration on virtual disks. In addition, I/O caching filters developed through vSphere APIs for I/O Filtering might require the virtual flash resource.

You can increase the capacity by adding more flash devices to the virtual flash resource.