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

Cloning a database with repmgr

As repmgr is a client/server PostgreSQL management suite, we need at least two nodes involved before we're really using it. We can perform the tasks outlined in this recipe as many times as we wish, creating several clones and registering them with repmgr. Of course, this book is for demonstration purposes, so we'll leave the larger clusters to you. With multiple nodes involved, the chances of data loss or system outages decline, which is excellent for our goal of high availability.

This recipe will focus on the process necessary to add a node to an existing repmgr cluster. The existing cluster in our case is the one that we established on pg-primary in the previous recipe.

Getting ready

This recipe depends on repmgr being installed on both a primary server and the clone that we will use. Please follow the Installing and configuring repmgr recipe before continuing.

How to do it...

For the purposes of this recipe, pg-primary will remain our master node, and the replica...