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 OmniPITR

We've stated on several occasions that WAL files are very important. Their role in PostgreSQL crash recovery, backup restoration, and replication gives them a central role in maintaining a high availability cluster. With OmniPITR, we can upgrade communication between servers to ensure that we have logging for every step of a WAL file's movement. This is no small benefit, and we can use it to audit the entire transmission path if we encounter a problem.

Though OmniPITR is a full suite of backup-related tools, we wish to focus on its ability to give us better control of WAL archival and recovery. As a consequence, this recipe will describe usage of the omnipitr-archive command.

Getting ready

This recipe depends on OmniPITR being installed on all servers that need to utilize it. Please follow the Installing and configuring OmniPITR recipe before continuing.

How to do it...

For this procedure, we will continue to use two servers. The backup server will still be named...