Understanding Clone Retention and Storage Costs in Snowflake

Alex, a Data Engineer at GlobalMart, thought cloning production tables and dropping the originals would free up storage. Two weeks later, finance team flagged a $12,000/month bill, the originals were gone, but the storage costs remained. Why? Zero-copy cloning isn't a storage hack, and understanding RETAINED_FOR_CLONE_BYTES is critical.

If you don't understand how Snowflake handles clone retention, you risk surprise storage bills, confused cost analysis, and incorrect capacity planning. Clones appear "free" until you drop the original, then the micro-partitions transfer ownership to the clone, and billing continues indefinitely.

In this masterclass you follow Alex's hands on journey where you will create tables, clone them, drop originals, and track storage metrics over Time Travel and Fail-safe periods. You'll query INFORMATION_SCHEMA and ACCOUNT_USAGE views to see exactly when and how storage ownership transfers. Test your understanding with scenario-based questions throughout.

What You'll Learn:

• How Snowflake shares micro-partitions between original and clone tables without duplicating data
• The storage lifecycle from creation through cloning, dropping, Time Travel, and Fail-safe periods
• What RETAINED_FOR_CLONE_BYTES measures and why it appears only after dropping the original table
• How to track storage metrics using INFORMATION_SCHEMA.TABLE_STORAGE_METRICS and SNOWFLAKE.ACCOUNT_USAGE.TABLE_STORAGE_METRICS
• Write monitoring queries to find all clones using CLONE_GROUP_ID and track retention costs across your account

By the end, you'll understand Snowflake's clone retention behavior, so you can accurately forecast storage costs, prevent billing surprises, and make informed decisions about when cloning is cost-effective versus creating filtered copies.