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Restoring PostgreSQL Backups to a Different Server with Barman

Introduction

Important Notice

This guide covers restoring PostgreSQL backups to a different server using Barman.
PostgreSQL and Barman setups are assumed to be already completed.

Restoring a PostgreSQL backup to a different server is crucial for:

  • Disaster recovery in case of hardware failure
  • Migration to a new environment
  • Creating a test environment based on production data

With Barman, this operation becomes straightforward and reliable.

Requirements

Before starting:

  • A valid base backup must exist in Barman.
  • Continuous WAL archiving must be configured.
  • A secondary server with PostgreSQL installed and ready.

Step 1: Prepare the Target Server

Ensure that PostgreSQL is installed on the new (target) server.

Install PostgreSQL:

Install PostgreSQL (Ubuntu/Debian)
sudo apt-get update
sudo apt-get install postgresql

or

Install PostgreSQL (RHEL/Rocky)
sudo yum install postgresql-server

Create an empty data directory:

Create Data Directory
sudo mkdir -p /database/PostgreSQL/13/main/
sudo chown postgres:postgres /database/PostgreSQL/13/main/

Data Directory Must Be Empty

Ensure the target data directory is completely empty before restoring the backup.

Step 2: Enable SSH Access for Recovery

Ensure the Barman server can SSH into the target server's postgres user without a password.

On the Barman server:

Setup SSH Access
su - barman
ssh-copy-id postgres@<target-server-ip>

Test SSH connectivity:

Test SSH
ssh postgres@<target-server-ip>

You should be logged in without needing a password.

Step 3: Initiate Recovery from Barman

Trigger the recovery process using the barman recover command.

Recover Backup to a Different Server
barman recover \
  --remote-ssh-command "ssh postgres@<target-server-ip>" \
  pg latest /database/PostgreSQL/13/main/

Replace <target-server-ip> with the IP address or hostname of your target server.

  • pg: Name of your Barman server configuration.
  • /database/PostgreSQL/13/main/: Data directory on the target server.

Custom Paths

You can adjust the target data directory path according to your server's PostgreSQL setup.

Step 4: Set the Restore Command on the Target Server

Edit or create the postgresql.auto.conf on the target server:

Set Restore Command on Target
restore_command = 'barman-wal-restore -P -U barman <barman-server-ip> pg %f %p'

Replace <barman-server-ip> with the IP address of your Barman server.

This allows PostgreSQL to pull any missing WAL segments from the Barman server during recovery.

Step 5: Start PostgreSQL Service on the Target Server

Finally, start PostgreSQL on the new server:

Start PostgreSQL on Target
sudo systemctl start postgresql

PostgreSQL will apply all WALs and complete the recovery process.

Check Server Version Compatibility

Ensure the PostgreSQL version on the source and target servers is identical or compatible to avoid recovery issues.

Conclusion

Restoring a PostgreSQL backup to a different server using Barman is a powerful technique for disaster recovery, server migrations, and cloning production environments for testing.

By following these steps, you can minimize downtime and ensure data consistency across servers!

Written by: Ruchan Yalçın | GitHub