What 10 PB of Cold Data Really Costs in AWS, GCP, Azure vs Tape Over 20 Years

“Cold” cloud storage isn’t cheap at scale. Parking 10 PB in AWS/GCP/Azure with just 2.5% monthly access still lands you in the $3–8M range over 10 years and $6–30M over 20 years, once you include storage, retrieval, and egress. A tape-backed object store sized for the same 10 PB (using realistic server/library/media/ops costs) plus a $500k one-time egress hit comes out around $2.3M over 10 years and $4.1M over 20 years—roughly $1–10M cheaper than staying in cloud cold tiers, depending on which tier you’re in. Cloud cold tiers = perpetual rent + metered reads. Tape = CapEx + stable OpEx, no per-GB retrieval tax. Over long horizons, the tape TCO curve flattens; the cloud curve doesn’t. Repatriation starts to make sense when you have:(a) ≥5–10 PB,(b) 10+ year retention,(c) low-but-steady access, and(d) real requirements for sovereignty, governance, and preservation. The punchline: keep fast-changing workloads in the cloud; move decade-scale archives to a preservation tier you own. Otherwise you’re renting your institutional memory indefinitely.