How to Set Up Incremental Backups with Borg

How to Set Up Incremental Backups with Borg

BorgBackup (Borg) is a deduplicating backup program that efficiently stores incremental backups with compression and encryption. It is one of the most space-efficient backup solutions available for your Breeze server, as it only stores changed data blocks between backups.

Installing Borg

# Ubuntu/Debian
sudo apt update && sudo apt install -y borgbackup

# RHEL/AlmaLinux/Rocky
sudo dnf install -y borgbackup

# Verify installation
borg --version

Initializing a Backup Repository

Create an encrypted repository for storing backups:

# Local repository
borg init --encryption=repokey /backup/borg-repo

# Remote repository via SSH
borg init --encryption=repokey ssh://backup-user@backup-server/~/borg-repo

Choose your encryption mode:

• repokey — encryption key stored in the repo (protected by passphrase)
• keyfile — encryption key stored locally (more secure, but key must be backed up separately)
• none — no encryption (not recommended for sensitive data)

Important: Back up your encryption key and passphrase separately. Without them, your backups are unrecoverable.

Creating Your First Backup

borg create --stats --progress \
  /backup/borg-repo::'{hostname}-{now:%Y-%m-%d_%H:%M}' \
  /home \
  /etc \
  /var/www \
  --exclude '*.pyc' \
  --exclude '/home/*/.cache' \
  --exclude '/var/www/*/node_modules'

Automated Backup Script

Create /usr/local/bin/borg-backup.sh:

#!/bin/bash
set -euo pipefail

export BORG_REPO="/backup/borg-repo"
export BORG_PASSPHRASE="your-secure-passphrase"
LOG="/var/log/borg-backup.log"

echo "$(date): Starting Borg backup" >> "$LOG"

# Create backup
borg create --stats --compression zstd,3 \
  ::'breeze-{now:%Y-%m-%d_%H:%M}' \
  /home \
  /etc \
  /var/www \
  /var/lib/mysql-backup \
  --exclude '*.pyc' \
  --exclude '*/node_modules' \
  --exclude '*/.cache' \
  2>&1 >> "$LOG"

# Prune old backups
borg prune --stats \
  --keep-daily=7 \
  --keep-weekly=4 \
  --keep-monthly=6 \
  2>&1 >> "$LOG"

# Compact repository to reclaim freed space
borg compact 2>&1 >> "$LOG"

echo "$(date): Backup completed successfully" >> "$LOG"

chmod +x /usr/local/bin/borg-backup.sh

Scheduling with Cron

# Run nightly at 2 AM
echo "0 2 * * * /usr/local/bin/borg-backup.sh" | sudo crontab -

Listing and Inspecting Backups

# List all archives
borg list /backup/borg-repo

# Show archive details
borg info /backup/borg-repo::breeze-2026-03-01_02:00

# List files in an archive
borg list /backup/borg-repo::breeze-2026-03-01_02:00 | head -50

Restoring Files

# Restore entire archive to current directory
cd /tmp/restore
borg extract /backup/borg-repo::breeze-2026-03-01_02:00

# Restore specific files or directories
borg extract /backup/borg-repo::breeze-2026-03-01_02:00 home/user/important-file.txt

# Restore to original location
cd /
borg extract /backup/borg-repo::breeze-2026-03-01_02:00 var/www/mysite

Pruning Strategy

Configure retention policies that match your needs:

borg prune \
  --keep-within=2d     \  # Keep all backups from last 2 days
  --keep-daily=7       \  # Keep 1 per day for 7 days
  --keep-weekly=4      \  # Keep 1 per week for 4 weeks
  --keep-monthly=12    \  # Keep 1 per month for 12 months
  --keep-yearly=2         # Keep 1 per year for 2 years

Best Practices

• Always encrypt your repository, especially for off-site backups
• Store the encryption key and passphrase in a separate, secure location
• Test restores regularly to verify backup integrity
• Use --compression zstd for the best balance of speed and compression ratio
• Run borg check periodically to verify repository consistency
• Dump databases to files before running Borg so they are in a consistent state
• Use borg compact after pruning to reclaim disk space on your Breeze server