Any operation that deletes the virtual LDEV ID of a volume used as a Thin Image Advanced volume cannot be performed.
When a GAD pair is deleted with the P-VOL specified, the virtual S-VOL's LDEV ID is deleted. If you delete the pair with the S-VOL specified, the P-VOL's virtual LDEV ID is deleted. When the virtual LDEV ID is deleted, the server does not recognize the volume, making it unusable as a Thin Image Advanced volume.