Have you worked with replication topologies? Tell about your experience.

In my experience working with databases, I have encountered various replication topologies, including master-slave (primary-secondary), master-master, and cascading replication.

For example, in one project, a master-slave replication was used for PostgreSQL, where the main server handled writes, and the slaves were read-only. This helped to offload the main server and increase fault tolerance. The setup included configuring parameters like wal_level, max_wal_senders, as well as configuring the slaves to receive and apply WAL records.

In another case, master-master replication was used on MySQL with Galera Cluster, which allowed writing on multiple nodes simultaneously and increased availability.

I also have experience setting up cascading replication, where a slave acts as a master for the next slave, which helps to scale reading to a large number of clients.

Overall, the choice of topology depends on the requirements for load, fault tolerance, and data consistency.