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

Formatting an XFS filesystem

The next and last part of our stack is the filesystem layer. This is where the PostgreSQL data will reside, so we need to ensure it's allocated properly. Unlike the underlying LVM layers, the filesystem is not so easily modified.

In this recipe, we will discuss some common formatting options and why we recommend them in addition to necessary commands.

Getting ready

Since this is the last layer in our complete stack, we strongly suggest following all the recipes up to Incorporating the second LVM layer before starting here.

How to do it...

Assuming pg1 is our current primary node, follow these steps there as the root user:

  1. Activate the second LVM volume with this command:
lvchange -a y VG_POSTGRES/LV_DATA
  1. Count the number of CPUs on the primary node.
  2. Multiply the CPU count by four.
  3. If the total in the previous step is less than 256, use 256.
  4. Use this command to find the Linux kernel version:
uname -r
  1. For kernel versions 3.0 and above, format the XFS filesystem with this command...