How to Self-Host Duplicati: Encrypted Cloud Backup 2026

TL;DR

Duplicati (LGPL, ~10K GitHub stars, C#) is a free backup client that stores encrypted, compressed backups on any cloud storage or remote server. Support for 25+ storage backends — S3, Backblaze B2, Google Drive, OneDrive, SFTP, WebDAV, and more. All backups are encrypted client-side with AES-256 before leaving your machine. Backblaze backup costs $7/month; CrashPlan costs $10/month. Duplicati + B2 storage costs ~$0.50/month for 100GB.

Key Takeaways

• Duplicati: LGPL, ~10K stars, C# — encrypted backup to cloud storage
• AES-256 encryption: Data encrypted before upload — storage provider can't read your files
• 25+ backends: S3, B2, GDrive, OneDrive, SFTP, WebDAV, Azure, FTP, local
• Deduplication: Block-level — only changed data is uploaded after initial backup
• Scheduling: Cron-like schedules with retention policies
• Web UI: Configure and monitor backups from the browser

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Duplicati vs Restic vs Borg vs CrashPlan

Feature	Duplicati	Restic	Borg	CrashPlan
Price	Free	Free	Free	$10/mo
UI	Web GUI	CLI only	CLI only	Desktop GUI
Encryption	AES-256	AES-256	AES-256	AES-256
Deduplication	Block-level	Content-defined	Content-defined	File-level
Cloud backends	25+	20+	SSH only	Cloud only
Setup difficulty	Easy	Medium	Medium	Easy
Scheduling	Built-in	External (cron)	External (cron)	Built-in
Restore	Web UI	CLI	CLI	Desktop app

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Part 1: Docker Setup

# docker-compose.yml
services:
  duplicati:
    image: lscr.io/linuxserver/duplicati:latest
    container_name: duplicati
    restart: unless-stopped
    ports:
      - "8200:8200"
    volumes:
      - duplicati_config:/config
      # Mount directories you want to back up:
      - /home:/source/home:ro
      - /etc:/source/etc:ro
      - /var/lib/docker/volumes:/source/docker-volumes:ro
      # Optional: local backup destination:
      - /mnt/backup:/backups
    environment:
      PUID: 1000
      PGID: 1000
      TZ: America/Los_Angeles

volumes:
  duplicati_config:

docker compose up -d

Visit http://your-server:8200 → set a web UI password when prompted.

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Part 2: HTTPS with Caddy

backup.yourdomain.com {
    reverse_proxy localhost:8200
}

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Part 3: Create a Backup Job

Step-by-step wizard

1. + Add Backup → Configure a new backup

2. General settings:

   • Name: Daily Server Backup
   • Encryption: AES-256 (default)
   • Passphrase: strong, unique passphrase (SAVE THIS — you cannot recover data without it)

3. Destination: Choose storage backend

Storage backends

Backend	Config
Backblaze B2	Bucket name, Application Key ID, Application Key
Amazon S3	Bucket, region, Access Key, Secret Key
Google Drive	OAuth login → select folder
SFTP	Host, port, username, SSH key or password
WebDAV	URL, username, password
OneDrive	OAuth login → select folder
Local/Network	Path: /backups/server1
MinIO	S3-compatible: endpoint, bucket, access key

Backblaze B2 example

Backend: B2 Cloud Storage
Bucket: my-server-backups
Folder: server1/
B2 Application Key ID: your-key-id
B2 Application Key: your-key

S3 example

Backend: S3 Compatible
Server: s3.amazonaws.com (or minio.yourdomain.com)
Bucket: backups
Region: us-east-1
Folder: server1/
AWS Access ID: AKIA...
AWS Access Key: your-secret-key

4. Source data: Select directories to back up

   • /source/home (home directories)
   • /source/etc (system configuration)
   • /source/docker-volumes (Docker data)

5. Schedule:

   • Frequency: Daily at 3:00 AM
   • Or: Every 6 hours

6. Options:

   • Keep backups: Smart retention (1/day for 7 days, 1/week for 4 weeks, 1/month for 12 months)
   • Block size: 100KB (default — good for dedup)
   • Upload speed limit: optional (don't saturate your connection)

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Part 4: Retention Policies

Smart retention (recommended)

Keep all backups for: 7 days
Keep 1 backup per week for: 4 weeks
Keep 1 backup per month for: 12 months
Delete everything older than: 1 year

Custom retention

Keep last: 30 versions

Unlimited retention

Keep all backups (unlimited)

Warning: Unlimited retention grows storage costs linearly. Smart retention is recommended.

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Part 5: Restore Files

Via web UI

1. Backups → [backup name] → Restore
2. Browse the backup tree — select files/folders
3. Choose restore point (date/time)
4. Restore to: original location or alternate path
5. Restore → files are downloaded, decrypted, and placed

Restore specific files

Restore → Search:
  *.conf                 — all config files
  /source/home/user/     — specific directory

Restore to different machine

1. Install Duplicati on the new machine
2. Point to the same storage backend
3. Restore from configuration → enter passphrase
4. Browse and restore any file

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Part 6: CLI Usage

# Run backup from command line:
docker exec duplicati duplicati-cli backup \
  "b2://my-bucket/server1?auth-username=KEY_ID&auth-password=KEY" \
  /source/home \
  --passphrase="your-encryption-passphrase" \
  --backup-name="CLI Backup"

# List backup versions:
docker exec duplicati duplicati-cli list \
  "b2://my-bucket/server1?auth-username=KEY_ID&auth-password=KEY" \
  --passphrase="your-encryption-passphrase"

# Restore a file:
docker exec duplicati duplicati-cli restore \
  "b2://my-bucket/server1?auth-username=KEY_ID&auth-password=KEY" \
  --passphrase="your-encryption-passphrase" \
  --restore-path=/tmp/restore \
  "home/user/important-file.txt"

# Verify backup integrity:
docker exec duplicati duplicati-cli test \
  "b2://my-bucket/server1?auth-username=KEY_ID&auth-password=KEY" \
  --passphrase="your-encryption-passphrase" \
  5   # verify 5 random file sets

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Part 7: Notifications

Email notifications

Settings → Add send mail advanced option:
  --send-mail-url=smtp://mail.yourdomain.com:587
  --send-mail-username=backup@yourdomain.com
  --send-mail-password=***
  --send-mail-from=backup@yourdomain.com
  --send-mail-to=you@yourdomain.com
  --send-mail-subject=Duplicati %OPERATIONNAME% - %PARSEDRESULT%
  --send-mail-level=Warning,Error,Fatal

Webhook (ntfy, Gotify, etc.)

Advanced Options:
  --send-http-url=https://ntfy.yourdomain.com/backups
  --send-http-message=%OPERATIONNAME% completed: %PARSEDRESULT%
  --send-http-result-output-format=Duplicati
  --send-http-level=Warning,Error,Fatal

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Part 8: Best Practices

What to back up

✅ Home directories (/home)
✅ Config files (/etc)
✅ Docker volumes (/var/lib/docker/volumes)
✅ Database dumps (pre-backup script)
✅ SSL certificates (/etc/letsencrypt)

❌ System binaries (/usr, /bin) — reinstall is faster
❌ Package cache (/var/cache)
❌ Temp files (/tmp)
❌ Docker images — re-pull is faster

Pre-backup database dumps

# Run-before script (add to backup job):
#!/bin/bash
# Dump all databases before backup:
docker exec postgres pg_dumpall -U postgres > /source/home/backups/postgres-all.sql
docker exec mysql mysqldump --all-databases -u root -p"$PASS" > /source/home/backups/mysql-all.sql

3-2-1 backup rule

• 3 copies of data (original + 2 backups)
• 2 different storage media (local + cloud)
• 1 offsite (cloud storage)

# Create 2 backup jobs:
# 1. Local backup (fast restore):
#    Destination: /mnt/backup/server1
#    Schedule: Every 6 hours
#
# 2. Cloud backup (disaster recovery):
#    Destination: B2/S3
#    Schedule: Daily at 3 AM

---

Maintenance

# Update:
docker compose pull
docker compose up -d

# Verify backup integrity (monthly):
# Backups → [job] → Commandline → Verify

# Check storage usage:
# Backups → [job] → Show log → backend statistics

# Compact/repair database:
docker exec duplicati duplicati-cli repair \
  "b2://bucket/path?auth-username=KEY&auth-password=SECRET" \
  --passphrase="your-passphrase"

# Logs:
docker compose logs -f duplicati

Why Self-Host Duplicati?

The case for self-hosting Duplicati comes down to three practical factors: data ownership, cost at scale, and operational control.

Data ownership is the fundamental argument. When you use a SaaS version of any tool, your data lives on someone else's infrastructure subject to their terms of service, their security practices, and their business continuity. If the vendor raises prices, gets acquired, changes API limits, or shuts down, you're left scrambling. Self-hosting Duplicati means your data and configuration stay on infrastructure you control — whether that's a VPS, a bare metal server, or a home lab.

Cost at scale matters once you move beyond individual use. Most SaaS equivalents charge per user or per data volume. A self-hosted instance on a $10-20/month VPS typically costs less than per-user SaaS pricing for teams of five or more — and the cost doesn't scale linearly with usage. One well-configured server handles dozens of users for a flat monthly fee.

Operational control is the third factor. The Docker Compose configuration above exposes every setting that commercial equivalents often hide behind enterprise plans: custom networking, environment variables, storage backends, and authentication integrations. You decide when to update, how to configure backups, and what access controls to apply.

The honest tradeoff: you're responsible for updates, backups, and availability. For teams running any production workloads, this is familiar territory. For individuals, the learning curve is real but the tooling (Docker, Caddy, automated backups) is well-documented and widely supported.

Server Requirements and Sizing

Before deploying Duplicati, assess your server capacity against expected workload.

Minimum viable setup: A 1 vCPU, 1GB RAM VPS with 20GB SSD is sufficient for personal use or small teams. Most consumer VPS providers — Hetzner, DigitalOcean, Linode, Vultr — offer machines in this range for $5-10/month. Hetzner offers excellent price-to-performance for European and US regions.

Recommended production setup: 2 vCPUs with 4GB RAM and 40GB SSD handles most medium deployments without resource contention. This gives Duplicati headroom for background tasks, caching, and concurrent users while leaving capacity for other services on the same host.

Storage planning: The Docker volumes in this docker-compose.yml store all persistent Duplicati data. Estimate your storage growth rate early — for data-intensive tools, budget for 3-5x your initial estimate. Hetzner Cloud and Vultr both support online volume resizing without stopping your instance.

Operating system: Any modern 64-bit Linux distribution works. Ubuntu 22.04 LTS and Debian 12 are the most commonly tested configurations. Ensure Docker Engine 24.0+ and Docker Compose v2 are installed — verify with docker --version and docker compose version. Avoid Docker Desktop on production Linux servers; it adds virtualization overhead and behaves differently from Docker Engine in ways that cause subtle networking issues.

Network: Only ports 80 and 443 need to be publicly accessible when running behind a reverse proxy. Internal service ports should be bound to localhost only. A minimal UFW firewall that blocks all inbound traffic except SSH, HTTP, and HTTPS is the single most effective security measure for a self-hosted server.

Backup and Disaster Recovery

Running Duplicati without a tested backup strategy is an unacceptable availability risk. Docker volumes are not automatically backed up — if you delete a volume or the host fails, data is gone with no recovery path.

What to back up: The named Docker volumes containing Duplicati's data (database files, user uploads, application state), your docker-compose.yml and any customized configuration files, and .env files containing secrets.

Backup approach: For simple setups, stop the container, archive the volume contents, then restart. For production environments where stopping causes disruption, use filesystem snapshots or database dump commands (PostgreSQL pg_dump, SQLite .backup, MySQL mysqldump) that produce consistent backups without downtime.

For a complete automated backup workflow that ships snapshots to S3-compatible object storage, see the Restic + Rclone backup guide. Restic handles deduplication and encryption; Rclone handles multi-destination uploads. The same setup works for any Docker volume.

Backup cadence: Daily backups to remote storage are a reasonable baseline for actively used tools. Use a 30-day retention window minimum — long enough to recover from mistakes discovered weeks later. For critical data, extend to 90 days and use a secondary destination.

Restore testing: A backup that has never been restored is a backup you cannot trust. Once a month, restore your Duplicati backup to a separate Docker Compose stack on different ports and verify the data is intact. This catches silent backup failures, script errors, and volume permission issues before they matter in a real recovery.

Security Hardening

Self-hosting means you are responsible for Duplicati's security posture. The Docker Compose setup provides a functional base; production deployments need additional hardening.

Always use a reverse proxy: Never expose Duplicati's internal port directly to the internet. The docker-compose.yml binds to localhost; Caddy or Nginx provides HTTPS termination. Direct HTTP access transmits credentials in plaintext. A reverse proxy also centralizes TLS management, rate limiting, and access logging.

Strong credentials: Change default passwords immediately after first login. For secrets in docker-compose environment variables, generate random values with openssl rand -base64 32 rather than reusing existing passwords.

Firewall configuration:

ufw default deny incoming
ufw allow 22/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable

Internal service ports (databases, admin panels, internal APIs) should only be reachable from localhost or the Docker network, never directly from the internet.

Network isolation: Docker Compose named networks keep Duplicati's services isolated from other containers on the same host. Database containers should not share networks with containers that don't need direct database access.

VPN access for sensitive services: For internal-only tools, restricting access to a VPN adds a strong second layer. Headscale is an open source Tailscale control server that puts your self-hosted stack behind a WireGuard mesh, eliminating public internet exposure for internal tools.

Update discipline: Subscribe to Duplicati's GitHub releases page to receive security advisory notifications. Schedule a monthly maintenance window to pull updated images. Running outdated container images is the most common cause of self-hosted service compromises.

Troubleshooting Common Issues

Container exits immediately or won't start

Check logs first — they almost always explain the failure:

docker compose logs -f duplicati

Common causes: a missing required environment variable, a port already in use, or a volume permission error. Port conflicts appear as bind: address already in use. Find the conflicting process with ss -tlpn | grep PORT and either stop it or change Duplicati's port mapping in docker-compose.yml.

Cannot reach the web interface

Work through this checklist:

1. Confirm the container is running: docker compose ps
2. Test locally on the server: curl -I http://localhost:PORT
3. If local access works but external doesn't, check your firewall: ufw status
4. If using a reverse proxy, verify it's running and the config is valid: caddy validate --config /etc/caddy/Caddyfile

Permission errors on volume mounts

Some containers run as a non-root user. If the Docker volume is owned by root, the container process cannot write to it. Find the volume's host path with docker volume inspect VOLUME_NAME, check the tool's documentation for its expected UID, and apply correct ownership:

chown -R 1000:1000 /var/lib/docker/volumes/your_volume/_data

High resource usage over time

Memory or CPU growing continuously usually indicates unconfigured log rotation, an unbound cache, or accumulated data needing pruning. Check current usage with docker stats duplicati. Add resource limits in docker-compose.yml to prevent one container from starving others. For ongoing visibility into resource trends, deploy Prometheus + Grafana or Netdata.

Data disappears after container restart

Data stored in the container's writable layer — rather than a named volume — is lost when the container is removed or recreated. This happens when the volume mount path in docker-compose.yml doesn't match where the application writes data. Verify mount paths against the tool's documentation and correct the mapping. Named volumes persist across container removal; only docker compose down -v deletes them.

Keeping Duplicati Updated

Duplicati follows a regular release cadence. Staying current matters for security patches and compatibility. The update process with Docker Compose is straightforward:

docker compose pull          # Download updated images
docker compose up -d         # Restart with new images
docker image prune -f        # Remove old image layers (optional)

Read the changelog before major version updates. Some releases include database migrations or breaking configuration changes. For major version bumps, test in a staging environment first — run a copy of the service on different ports with the same volume data to validate the migration before touching production.

Version pinning: For stability, pin to a specific image tag in docker-compose.yml instead of latest. Update deliberately after reviewing the changelog. This trades automatic patch delivery for predictable behavior — the right call for business-critical services.

Post-update verification: After updating, confirm Duplicati is functioning correctly. Most services expose a /health endpoint that returns HTTP 200 — curl it from the server or monitor it with your uptime tool.

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See also: Restic + Rclone — CLI-first backup with more advanced deduplication

See all open source DevOps tools at OSSAlt.com/categories/devops.