I'm not aware of AWS ever confirming tape for glacier. My own speculation is they likely use hdd for glacier - especially so for the smaller regions - and eat the cost.
Someone recently came across some planning documents filed in London for a small "datacenter" which wasn't attached to their usual London compute DCs and built to house tape libraries (this was explicitly called out as there was concern about power - tape libraries don't use much). So I would be fairly confident they wait until the glacier volumes grow enough on hdd before building out tape infra.
Someone recently came across some planning documents filed in London for a small "datacenter" which wasn't attached to their usual London compute DCs and built to house tape libraries (this was explicitly called out as there was concern about power - tape libraries don't use much). So I would be fairly confident they wait until the glacier volumes grow enough on hdd before building out tape infra.