Multi-master replication is a relatively new concept within the PostgreSQL world that allows more than one node to accept writes and all nodes to contain the same data regardless of origin. The concept of how the multi-master approach works is generally easy to understand if we examine the workflow of how it is implemented between two nodes.
This chapter will explore the inherent limitations of multi-master database technology as applied to PostgreSQL, as well as how to best utilize it to maximize application availability.
In this chapter, we will learn how multiple writable PostgreSQL nodes affect the concept of high availability. We will cover the following topics in this chapter:
- Deciding whether multi-master is right for you
- Obtaining and installing BDR
- Starting with a single BDR node
- Creating an additional BDR node
- Testing...