Storage Tiering

Concepts covered: paDataLake

What They Want to Hear 'Not all data is accessed equally. I tier data by access pattern: hot (SSD, recent days/weeks, most expensive), warm (standard S3, recent months), cold (Glacier, historical years, cheapest). This alone can cut storage bills by 60-80% because the 80/20 rule applies: 80% of queries touch 20% of data.'

About This Interactive Section

This section is part of the Where Data Lives: Intermediate lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

How DataDriven Lessons Work

DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.