How does Weaviate handle replication and consistency?

Weaviate supports synchronous replication across nodes with configurable consistency levels for reads and writes, from ONE acknowledgment for low latency to ALL for strong consistency. The replication factor is set per collection and determines how many copies of each shard exist in the cluster. Writes go to the configured quorum before returning success, giving tunable trade-offs between durability, latency, and availability. Weaviate uses a Raft-based consensus for schema changes and cluster metadata, while vector data replicates through a separate path.