v.20.10New Feature

When Writing Duplicate Blocks to Replicas, Ensure Local Writing Instead of Ignoring

When duplicate block is written to replica where it does not exist locally (has not been fetched from replicas), don't ignore it and write locally to achieve the same effect as if it was successfully replicated. #11684 (alexey-milovidov).
Improved handling of duplicate data blocks on replicas by writing them locally when they do not exist, ensuring consistent replication state.

Why it matters

This feature addresses the issue where duplicate blocks received by a replica, but not present locally because they were never fetched from other replicas, were previously ignored. By writing such blocks locally, the replica achieves the same state as if the data was successfully replicated, improving data consistency and reliability across replicas.

How to use it

This behavior is applied automatically in replicas; users do not need to manually enable it. The system now writes duplicate blocks locally even if they were not fetched before, ensuring seamless replication without additional configuration.