Comment 1 for bug 1957848

Okay, after some further investigation - the pure storage backend used in this scenario should not be using the slow path volume copy when an instance is booted from an image backed by a cinder volume.

The slow path is taken for backends that cannot do an efficient clone (pure storage can), but only if allowed_direct_url_schemes in the cinder.conf is set and includes the 'cinder' label [0] - which it does not by default and that logic was not added as part of the Cinder backend for Glance enablement. I do not think it hurts to include this option by default.

[0] - https://opendev.org/openstack/cinder/src/branch/stable/yoga/cinder/volume/flows/manager/create_volume.py#L1077

        # Try and clone the image if we have it set as a glance location.
        if not cloned and 'cinder' in CONF.allowed_direct_url_schemes:
            model_update, cloned = self._clone_image_volume(context,
                                                            volume,
                                                            image_location,
                                                            image_meta)