Learn pgBackRest - Prerequisite Skills & Environment Setup

#Introduction

Welcome to the Learn pgBackRest series! This series will take you to mastery of pgBackRest — a reliable, parallel, and scalable PostgreSQL backup & restore solution — from its architecture (repository, stanza, WAL archiving) to configuration, retention, encryption, and production practices for large databases. There are 23 episodes in total, organized into six phases, from conceptual foundations all the way to production readiness.

Before you run pgbackrest backup --type=full, there are foundational skills and tools you must have. Why do these prerequisites matter? Because pgBackRest works at the lowest layer of PostgreSQL: it leverages WAL archiving, communicates with the database server through libpq, and stores files into a repository. Without understanding these layers, you'll struggle to diagnose why archive-push fails or why a restore isn't consistent.

Episode 0 is your roadmap: we'll make sure the foundational skills are in place, set up PostgreSQL, install pgBackRest 2.59.0, create the repository directory, and verify the environment for the first time.

#Foundational Skills You Must Have

#PostgreSQL Basics

You should be comfortable with PostgreSQL's core concepts: the cluster (a set of databases managed by a single instance), psql (the client), pg_ctl (server control), and especially WAL (Write-Ahead Log). WAL is the transaction log that enables point-in-time recovery — it's the very heart of how pgBackRest works. Practice the following:

psql -U postgres -c "SELECT version();"
pg_ctl status -D /var/lib/postgresql/16/main

Also understand pg_hba.conf (connection authentication) and postgresql.conf (server configuration) — pgBackRest touches both, particularly the archive_mode and archive_command parameters.

#Linux: Users, systemd, and Permissions

pgBackRest runs as a binary invoked by PostgreSQL (via archive_command) as well as by a scheduler (cron/systemd timer). You must understand user management (useradd), services (systemctl), and file permissions (owner/group/mode). The most common source of problems in production: the repository directory is owned by the wrong user, causing archive-push to fail with permission denied.

#Storage: Mount, NFS, and Object Storage

The pgBackRest repository can live on local disk, an NFS mount, or object storage (S3-compatible). You need to understand the concepts of mount points, disk size and space, and latency. Remember: a good backup is meaningless if it's stored on the same disk as the database — we'll discuss off-site backups in episode 12.

#Software and Hardware to Prepare

#PostgreSQL 13-18 Installed

This series uses PostgreSQL in the version range 13 to 18 — pgBackRest 2.59.0 supports up to 10 PostgreSQL versions at once. Make sure one version is installed and running as a service:

psql -U postgres -c "SHOW server_version;"
systemctl status postgresql

If it's not installed yet, install it from the distribution repository or PGDG (PostgreSQL Global Development Group):

sudo apt install -y postgresql-16

#pgBackRest 2.59.0

Install pgBackRest 2.59.0 (released 20 July 2026) — the current stable release. From the distribution package:

sudo apt install -y pgbackrest
pgbackrest version

pgbackrest version should print pgbackrest 2.59.0. Alternatively, you can build from source (we'll cover this in more depth in episode 3).

#Repository Directory

Create the repository directory owned by the postgres user. The default pgBackRest location is /var/lib/pgbackrest:

sudo mkdir -p /var/lib/pgbackrest
sudo chown -R postgres:postgres /var/lib/pgbackrest

This directory will later hold the stanza and all backup files.

#SSH for Remote Mode

Remote mode (repository on another host, or database on another host) requires SSH with key authentication. Make sure ssh is installed and the key has been generated:

ssh-keygen -t ed25519 -N "" -f ~/.ssh/id_ed25519

We'll configure remote mode in full in episodes 12 and 13. For now, just make sure SSH works without a password.

#Environment Verification

Before moving on to episode 1, run a thorough verification:

pgbackrest version
psql -U postgres -c "SELECT version();"
ls -ld /var/lib/pgbackrest
ssh -o BatchMode=yes localhost true

All four commands must succeed: version 2.59.0, PostgreSQL responding, the repository directory owned by postgres, and SSH running without a password prompt.

#Prerequisite Summary

Here's what you've prepared in episode 0:

• PostgreSQL skills: cluster, WAL, psql, pg_ctl, pg_hba.conf.
• Linux skills: users, systemd, file permissions, mounts.
• PostgreSQL 13-18: one version installed and running.
• pgBackRest 2.59.0: installed, pgbackrest version prints the version.
• Repository: /var/lib/pgbackrest owned by the postgres user.
• SSH: key authentication ready for remote mode.

If anything is missing, stop here and complete it before continuing. The 22-episode journey ahead will go much more smoothly with this strong foundation.

#Conclusion

Key takeaways:

• pgBackRest works at the WAL and file-system layer — master PostgreSQL and Linux fundamentals first.
• Install PostgreSQL 13-18 and pgBackRest 2.59.0 (released 20 July 2026).
• The repository directory /var/lib/pgbackrest must be owned by the postgres user.
• Prepare SSH key authentication for remote mode.
• Never put the repository on the same partition as the database data.

In the next episode we'll cover the history, background, and why you need pgBackRest — from its inception at Crunchy Data in 2014, the limitations of the fragile pg_basebackup + WAL archiving scripts, to the parallel backup, continuous WAL archiving, precise PITR, and retention policy features that made it the modern standard for PostgreSQL backups. Make sure your environment is ready, because the Learn pgBackRest journey has only just begun!