01medium.com
How We Migrated Europe’s Largest Data Lake: On Time and Without Turning the Lights Off
Booking.com migrated approximately 80–90 PB from on-premises Hadoop 2 to the Booking Data Exchange (BDX) in one year while keeping business operations running. BDX uses AWS S3 and Snowflake as its data-lakehouse foundation. The program included thousands of tables and workflows across dozens of teams, supported by a Migration UI, an Airflow wrapper, sequential migration waves, detailed documentation, training for hundreds of users, and parallel dependency management. The effort also removed obsolete data and strengthened scalability, governance, and data capabilities.