It was never confirmed, but I recall this[1] article making a pretty persuasive case Glacier was using optical disks. [1]https://storagemojo.com/2014/04/25/ama

It was never confirmed, but I recall this[1] article making a pretty persuasive case Glacier was using optical disks. [1]https://storagemojo.com/2014/04/25/amazons-glacier-secret-bdxl/ https://storagemojo.com/2014/04/25/amazons-glacier-secret-bd...