In this chapter, we outlined the basic concept of synchronous replication, and showed how data can be replicated synchronously. We also showed how durability requirements can be changed on the fly by modifying PostgreSQL runtime parameters. PostgreSQL gives users the choice of how a transaction should be replicated, and which level of durability is necessary for a certain transaction.

In the next chapter, we will dive into monitoring and see how we can figure out whether our replicated setup is working as expected.