In the previous chapter, we saw how to move data from one PostgreSQL cluster to another or from one database in a cluster to another in the same cluster. We also covered various options that can be used while creating the files that are used to move data. How can we restore the data from a file to a database cluster and what are the options available while restoring the data were also covered.

In this chapter, we will cover a few concepts about scalability and failover. Then, we will see a couple of ways of achieving scalability and failover-ability with tools available in the PostgreSQL ecosystem.

Scalability and ability to recover from failures are critical for databases. These are two different concepts, although the same tool or approach can take care of both. We will first look at scalability and then at the ability to recover from failures.