Explain advanced database replication topologies and consistency models in PHP systems.

Database replication distributes data across nodes to improve availability, read scalability, and disaster recovery, while introducing consistency trade-offs.

Replication is fundamental to high availability systems.

Types of replication:

Writes go to primary, reads from replicas.

Multiple writable nodes.

Strong consistency but higher latency.

Better performance but eventual consistency.

Consistency models:

All reads see latest writes.

Replicas converge over time.

Preserves event order causally related operations.

Advanced challenges:

1.…