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

Managing WAL files with WAL-E

With WAL-E installed, we can now use it to transmit transaction logs to and from our cloud service of choice. Remember, by keeping WAL files in a remote location, they're isolated from natural disasters, datacenter outages, being overwritten, and any number of unplanned events. Consider cloud storage a form of long-term archival of our transaction logs.

Why is this important? Remember our mantra: outages are unavoidable. We can take multiple steps to avoid them, but sometimes the situation is beyond human intervention. Sometimes we simply need to rebuild.

An offsite backup of WAL files means we can apply PITR to a recent backup and reach the last known stable state of our data. Since WAL-E integrates directly into the PostgreSQL transaction log archival process, the WAL files we preserve are as fresh as possible.

Let's see how it works.

Getting ready

Before continuing with this recipe, please complete the steps in the Installing and configuring WAL-E recipe.

How to...