Migrate data to Delta Lake

Databricks provides tools to simplify the migration of Parquet and Iceberg data into Delta Lake.

When to use CONVERT TO DELTA vs. CLONE

The CONVERT TO DELTA SQL command performs a one-time, in-place conversion of Parquet and Iceberg tables into external tables. See Convert to Delta Lake.

CLONE support for Parquet and Iceberg extends CONVERT TO DELTA functionality to include incremental support for conversion. You can use DEEP CLONE to create Unity Catalog managed tables. See Incrementally clone Parquet and Iceberg tables to Delta Lake.

Databricks recommends storing data using Unity Catalog managed tables, but in-place conversion provides many of the same benefits without needing to fully rewrite all data. Databricks recommends using CLONE if the source system continues to receive updates during the migration.