How AWS S3 is built

January 21, 2026

AI Summary

5 min read

🎙️ The Voices & The Context

The Format: In-depth technical interview with Q&A on AWS S3's engineering secrets.
The Key Players:
- Guest: Mylon, VP of Data & Analytics at AWS; ran S3 for 13 years. Expert on massive-scale storage, sharing rare internal details.
- Host: Gergely Orosz (Pragmatic Engineer podcast), probing engineer asking smart follow-ups on scale, failures, and evolution.
The Vibe: Educational and awe-inspiring; mixes mind-blowing stats with deep distributed systems geekery—intense for tech fans, fascinating "wow" moments for general audiences.

🗝️ Key Themes & Topics

The episode dives into S3's unimaginable scale, evolution from simple object storage to AI-ready primitives, and hardcore engineering for reliability at planetary levels. Core discussions: sheer size, consistency upgrades, failure-proofing, and future-proof data tools.

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What you'll learn

1 (00:00) **🎙️ Introduction: Mylon LeFevre**
2 (01:04) **Current Scale of S3**
3 (03:48) **History and Evolution of S3**
4 (09:45) **S3 Basics: Architecture and Primitives**
5 (13:36) **S3 Pricing Strategy**
6 (19:37) **From Eventual to Strong Consistency**
7 (29:02) **Ensuring Correctness with Formal Methods**

+ Full timestamped outline available in the app

Show Notes

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Amazon S3 is one of the largest distributed systems ever built, storing and serving data for a significant portion of the internet. Behind its simple interfaces hides an enormous amount of engineering work, careful tradeoffs, and long-term thinking.

In this episode, I sit down with Mai-Lan Tomsen Bukovec, VP of Data and Analytics at AWS, who has been running Amazon S3 for more than a decade. Mai-Lan shares how S3 operates at extreme scale, what it takes to design for durability and availability across millions of servers, and why building for failure is a core principle.

We also go deep into how AWS approaches correctness using formal methods, how storage tiers and limits shape system design, and why simplicity remains one of the hardest and most important goals at S3’s scale.

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Timestamps

(00:00) Intro

(01:03) S3’s scale

(03:58) How S3 started

(07:25) Parquet, Iceberg, and S3 tables

(09:46) S3 for developers

(13:37) Why AWS keeps S3 prices low

(17:10) AWS pricing tiers

(19:38) Availability and durability

(26:21) The cost of S3's consistency

(31:22) Automated reasoning and proof of correctness