Zero Copy Replication bug causes cluster-wide data deletion in ClickHouse

ClickHouse's experimental Zero Copy Replication feature contains critical bugs where deletion logic on one replica can delete shared S3 objects for all replicas. When a mutation operation triggers the bug, a replica erroneously believes all data parts are unreferenced and deletes them from S3, affecting the entire cluster. The feature has been unmaintained for 4 years.

Immediately disable Zero Copy Replication on all ClickHouse clusters. Conduct full audit of ClickHouse configuration to remove experimental features from production. Enable S3 Versioning on storage buckets to allow recovery from application-layer deletes. Implement monitoring for S3 object deletions and cold storage integrity checks.