Book Image

PostgreSQL High Availability Cookbook - Second Edition

By : Shaun Thomas
Book Image

PostgreSQL High Availability Cookbook - Second Edition

By: Shaun Thomas

Overview of this book

Databases are nothing without the data they store. In the event of a failure - catastrophic or otherwise - immediate recovery is essential. By carefully combining multiple servers, it’s even possible to hide the fact a failure occurred at all. From hardware selection to software stacks and horizontal scalability, this book will help you build a versatile PostgreSQL cluster that will survive crashes, resist data corruption, and grow smoothly with customer demand. It all begins with hardware selection for the skeleton of an efficient PostgreSQL database cluster. Then it’s on to preventing downtime as well as troubleshooting some real life problems that administrators commonly face. Next, we add database monitoring to the stack, using collectd, Nagios, and Graphite. And no stack is complete without replication using multiple internal and external tools, including the newly released pglogical extension. Pacemaker or Raft consensus tools are the final piece to grant the cluster the ability to heal itself. We even round off by tackling the complex problem of data scalability. This book exploits many new features introduced in PostgreSQL 9.6 to make the database more efficient and adaptive, and most importantly, keep it running.
Table of Contents (18 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Setting up a hot standby

It is a very good practice, if not an outright requirement, to have a second online copy of a PostgreSQL server in high availability clusters. Without such an online server, recovery from an outage may require hours of incidence response, backup recovery, and server provisioning. We have everything to gain by having extra online servers.

In addition, the process of setting up a hot standby acts as the basis for creating PostgreSQL streaming replicas. This means that we can reuse this recipe over and over again anytime we need to create PostgreSQL mirrors, provision extra backup copies, set up test instances, and so on.

All of this is made possible by the pg_basebackup command.

Getting ready

A hot standby server should have similar, if not exactly the same, specifications as the PostgreSQL server it is subscribed to. Try to accomplish this if possible. Also refer to the previous Securing the WAL stream recipe, as we will be consuming WAL files in this recipe.

How to do...