A device's vStorage API for Array Integration (VAAI) support status command line output shows: naa.500253825002a865 VAAI Plugin Name: ATS Status: unsupported Clone Status: unsupported Zero Status…

The vSphere Web Client maps VAAI status to 'Unknown' when a device supports only some VAAI primitives - here Zero Status is supported but ATS, Clone, and Delete are unsupported. 'Supported' requires all primitives to be active, and 'Unsupported' requires all to be inactive, so partial support produces the 'Unknown' designation.

'Supported' cannot apply because three of the four VAAI primitives - ATS, Clone, and Delete - all report as unsupported in the CLI output.

'Not supported' is not a valid VAAI status label in the vSphere Web Client - the three valid statuses are Supported, Unknown, and Unsupported.

'Unsupported' would only apply if every VAAI primitive reported as unsupported, but Zero Status is explicitly listed as supported in this output.