Migrating Proprietary Warehouses to Open Lakehouses: The 2026 Playbook for Zero-Copy Metadata Translation

This article provides a comprehensive guide for migrating proprietary data warehouses to open lakehouses in 2026, focusing on zero-copy metadata translation. It explains why warehouse migrations often fail due to hidden dependencies, undocumented processes, and treating migrations as storage moves rather than operating-model changes. The playbook covers key concepts like what zero-copy really means, using Apache Iceberg as a migration target, query federation for business continuity, staged migration blueprints, validation strategies, security and access control, and common mistakes to avoid. It emphasizes reducing vendor lock-in, preserving access during transitions, and ending with an open lakehouse supporting multiple engines. Aimed at IT professionals and data engineers, it offers practical runbooks for the first 90 days and discusses data contracts, rollback plans, and preparing for the agentic lakehouse.