For each storage device and datastore, the vSphere Web Client display the hardware acceleration support status.
The status values are Unknown, Supported, and Not Supported. The initial value is Unknown.
For block devices, the status changes to Supported after the host successfully performs the offload operation. If the offload operation fails, the status changes to Not Supported. The status remains Unknown if the device provides partial hardware acceleration support.
With NAS, the status becomes Supported when the storage can perform at least one hardware offload operation.
When storage devices do not support or provide partial support for the host operations, your host reverts to its native methods to perform unsupported operations.