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

Examining /proc/net/bonding/bond0

Highly-available databases often come in pairs for redundancy purposes. These servers can have any number of procedures to keep the data synchronized, and this book suggests direct connections when possible. Direct connections between servers ensure fast communication between redundant servers, and it resembles the following network design:

In some cases, it can be advantageous to connect the database servers to a general network fabric. Depending on the interaction of the upstream network devices, this can significantly increase the network packet's round-trip-time (RTT). This is usually fine for PostgreSQL replication, but OLTP systems may be more sensitive. Block-level replication systems, such as DRBD, which operate beneath the filesystem, fare even worse.

Each of our database servers should be equipped with at least two independent network interfaces. In order to prevent downtime, these interfaces must be linked with a bond. Network bonds act as an abstraction...