Architecture 
Twenty Years of S3: How It Became the Default Persistence Layer for Modern Data Infrastructure
S3 launched twenty years ago as a simple object store with eventual consistency. Strong consistency, conditional writes, and Express One Zone turned it into the durable source of truth for warehouses, streaming systems, databases, and now Git hosting.
Bigtable at Twenty: What Stayed and What Got Rebuilt
SIGMOD Companion ’26 has a 13-page paper by 50+ Google authors revisiting Bigtable two decades on. 10 EB, 7 billion QPS, and an architecture that barely moved. This is my reading of why.