How to Create Incremental Backups in Debian 12 Bookworm

Creating reliable and consistent backups is a fundamental part of system administration. Whether you’re managing a server, desktop, or development environment, backups ensure that your data can be recovered in case of hardware failure, accidental deletion, or other mishaps. In this post, we’ll focus on how to create incremental backups in Debian 12 Bookworm, using tried and tested command-line tools that are powerful, efficient, and well-integrated with the Debian ecosystem.

📦 What Are Incremental Backups?

Before diving into implementation, it’s essential to understand what incremental backups are.

An incremental backup only copies files that have changed since the last backup (whether that’s full or incremental). This makes incremental backups significantly faster and more space-efficient compared to full backups, which duplicate all files every time.

There are three primary backup types:

• Full backup: A complete copy of all selected files.
• Incremental backup: Copies only files that have changed since the last backup.
• Differential backup: Copies files changed since the last full backup.

✅ Why Use Incremental Backups on Debian?

Debian 12 Bookworm provides a stable foundation for systems that require reliability and control. Incremental backups are ideal in such environments because:

• They minimize storage requirements.
• Speed up backup processes by only copying changed data.
• Enable frequent snapshots without consuming much bandwidth or CPU time.
• Allow quick restores using a combination of full and incremental backups.

🛠️ Tools to Create Incremental Backups in Debian

There are several tools available on Debian 12 to create incremental backups. Some of the most common include:

• rsync
• tar
• borgbackup
• rdiff-backup
• duplicity

For this article, we’ll focus on rsync, borgbackup, and rdiff-backup — each with its strengths and suitable for different use cases.

🔁 Method 1: Incremental Backups Using rsync

🔍 What is rsync?

rsync is a fast, versatile file copying tool. While it’s often used for synchronizing directories, it can also perform incremental backups using hard links and archive modes.

🧱 Setup

First, install rsync:

sudo apt update
sudo apt install rsync

📂 Directory Structure

Let’s assume you want to back up /home/user/data to /mnt/backup.

You can structure the backup directory like this:

/mnt/backup/
├── backup-2024-04-01/
├── backup-2024-04-02/

🧪 Performing the First Full Backup

rsync -a --delete /home/user/data/ /mnt/backup/backup-2024-04-01/

🔄 Creating Incremental Backups with Hard Links

The key to incremental backups with rsync is using the --link-dest option, which compares the current backup with a previous one and hard-links unchanged files to save space.

rsync -a --delete --link-dest=/mnt/backup/backup-2024-04-01/ \
  /home/user/data/ /mnt/backup/backup-2024-04-02/

This approach saves storage space by reusing unchanged files.

🧹 Automating with Cron

You can set up a daily cron job to run this automatically:

crontab -e

Add this line:

0 2 * * * /usr/bin/rsync -a --delete --link-dest=/mnt/backup/backup-$(date -d "yesterday" +\%F)/ /home/user/data/ /mnt/backup/backup-$(date +\%F)/

🔐 Method 2: Incremental Backups Using BorgBackup

🔍 What is BorgBackup?

BorgBackup is a deduplicating backup program that supports compression and encryption. It’s perfect for those who want a more robust and modern backup solution.

🧱 Install Borg on Debian 12

sudo apt update
sudo apt install borgbackup

📁 Initialize a Backup Repository

Let’s create a new backup repository in /mnt/borg-backups:

borg init --encryption=repokey /mnt/borg-backups

You’ll be prompted to enter a passphrase for encryption.

🗂️ Create the First Backup (Archive)

borg create --stats /mnt/borg-backups::first-backup /home/user/data

🔁 Subsequent Incremental Backups

Borg will automatically store only the changed data blocks between backups, so all subsequent backups are incremental:

borg create --stats /mnt/borg-backups::backup-$(date +%F) /home/user/data

📋 Listing Archives

borg list /mnt/borg-backups

♻️ Pruning Old Backups

Borg includes a handy prune command to automatically delete old backups:

borg prune -v --keep-daily=7 --keep-weekly=4 --keep-monthly=6 /mnt/borg-backups

This keeps 7 daily, 4 weekly, and 6 monthly backups.

🔁 Method 3: Incremental Backups with rdiff-backup

🔍 What is rdiff-backup?

rdiff-backup is a simple yet powerful tool that combines the best features of rsync and version control. It stores reverse diffs so you can restore files to their state at any given time.

🧱 Install rdiff-backup

sudo apt update
sudo apt install rdiff-backup

🧪 Perform Initial Backup

rdiff-backup /home/user/data /mnt/rdiff-backups

🔄 Subsequent Incremental Backups

You can run the same command again — rdiff-backup automatically creates reverse diffs:

rdiff-backup /home/user/data /mnt/rdiff-backups

🕓 List Backup Increments

rdiff-backup --list-increment-sizes /mnt/rdiff-backups

⏪ Restore to Previous State

To restore to a specific time (e.g., 3 days ago):

rdiff-backup -r 3D /mnt/rdiff-backups /home/user/data-restored

🧩 Choosing the Right Tool

🔒 Securing Your Backup Strategy

A backup is only as good as its protection. Keep these in mind:

• Use encryption (especially with Borg) if storing backups on external or remote drives.
• Test restore procedures regularly.
• Automate backups with cron, systemd timers, or Anacron.
• Store backups offsite when possible (e.g., cloud, remote server).
• Check backup integrity regularly using tools like borg check.

📌 Summary

Creating incremental backups in Debian 12 Bookworm can be done effectively using tools like rsync, borgbackup, or rdiff-backup. Whether you’re a beginner or a seasoned sysadmin, there’s a solution that fits your workflow.

To recap:

• Use rsync for simple, fast local backups with hard links.
• Use borgbackup if you want deduplication, encryption, and advanced pruning.
• Use rdiff-backup for a nice balance between simplicity and versioning.

No matter which method you choose, the most important part is consistency — back up frequently, test your restores, and stay protected.

🔄 Next Steps

• Set up a script to automate your backup of choice.
• Explore remote backups using SSH.
• Consider integrating your backup with cloud storage using rclone + your favorite backup tool.