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

Preparing systems for the stack

Before we can use LVM, DRBD, or XFS on our servers, we must take some preliminary steps. We've never encountered a Linux system that is optimized for this kind of advanced usage directly after installation. In this recipe, we will modify several configuration files and even reboot the server.

We're trying to put each system in a standard state that we'll use for all future database servers. This means that LVM needs to ignore some devices to prevent disrupting DRBD, the initial RAM disks during a boot should reflect this same allocation, and device performance shouldn't be lost between abstraction layers. We also need all of the tools that we'll use throughout this chapter.

This recipe will guarantee that these criteria are true, so be prepared!

Getting ready

The only things we should need at this point are the ability to run commands as root and a device dedicated to database storage. However, if you are running a RHEL system (not a derivative such as CentOS...