Zero-Copy Mirroring to Open Iceberg Tables

This article provides a detailed analysis of zero-copy mirroring as a migration strategy from proprietary data warehouses to open Apache Iceberg tables. It clarifies the true meaning of zero-copy, distinguishing between true zero-copy, minimal-copy, and phased-copy scenarios based on data format and accessibility. The article outlines a staged migration playbook: assess schemas and catalog dependencies, translate physical files into Iceberg tables, rebuild business logic in the semantic layer, keep data fresh during migration, validate before cutover, and avoid common pitfalls. It emphasizes that true zero-copy works only when source data is in Parquet format and accessible in object storage, and recommends Dremio as a fitting tool for this migration path. The content is technical, focused on IT/data engineering best practices.