Docker Volumes store data independently from containers but require separate approach for backup. This guide describes universal methods for working with volumes using popular services as examples.

💡 Replace volume names with your own. Methods work with any containers.

📦 Backup volumes

docker run --rm \
  -v portainer_data:/backup/portainer_data \
  -v postgres_data:/backup/postgres_data \
  -v redis_data:/backup/redis_data \
  -v /opt/docker/backup:/archive \
  --entrypoint backup \
  offen/docker-volume-backup:v2

Parameters:

ParameterDescription
-v <volume>:/backup/<name>Map volume to backup directory
-v /opt/docker/backup:/archiveWhere to save archive on host
--entrypoint backupRun backup mode
--rmRemove container after completion

Why this method:

  • ✅ One container - all volumes
  • ✅ Automatic tar.gz compression
  • ✅ No service stop required (for most scenarios)
  • ✅ Suitable for cron automation

Alternative: via tar directly

# Single volume backup
docker run --rm \
  -v postgres_data:/volume:ro \
  -v /opt/docker/backup:/backup \
  alpine tar czf /backup/postgres-$(date +%F).tar.gz -C /volume .

Features:

  • :ro - read-only, protects from modification during backup
  • Direct archive creation without intermediate scripts
  • Suitable for one-time operations

🔄 Restore from backup

Step 1: Extract archive

tar -C /tmp -xvf backup-*.tar.gz

Step 2: Copy data to volumes

# Portainer
docker run -d --name tmp-portainer -v portainer_data:/restore alpine
docker cp /tmp/backup/portainer_data tmp-portainer:/restore
docker stop tmp-portainer && docker rm tmp-portainer

# PostgreSQL
docker run -d --name tmp-postgres -v postgres_data:/restore alpine
docker cp /tmp/backup/postgres_data tmp-postgres:/restore
docker stop tmp-postgres && docker rm tmp-postgres

# Redis
docker run -d --name tmp-redis -v redis_data:/restore alpine
docker cp /tmp/backup/redis_data tmp-redis:/restore
docker stop tmp-redis && docker rm tmp-redis

Why via temporary containers:

  • Direct volume access from host is complex (path in /var/lib/docker/volumes/)
  • docker cp preserves file permissions and attributes
  • Containers removed after copy - clean and safe

Recommendation

# Stop services before restore
docker compose stop postgres redis portainer

# Perform restore

# Start services
docker compose start

🔀 Migrate volumes

Copy to new volume

docker volume create new_volume && \
docker run --rm -it \
  -v old_volume:/from \
  -v new_volume:/to \
  alpine ash -c 'cd /from && cp -av . /to'

Breakdown:

  • docker volume create - creates target volume
  • -v old_volume:/from - mounts source
  • -v new_volume:/to - mounts destination
  • cp -av - copies with preserved permissions (-a) and progress (-v)

When to use:

  • Renaming volume
  • Migrating to different storage driver
  • Cleaning from temp files (copy only needed data)

Cross-host migration

# Source host: create archive
docker run --rm \
  -v postgres_data:/data \
  -v /backup:/archive \
  alpine tar czf /archive/postgres.tar.gz -C /data .

# Copy to new host
scp /backup/postgres.tar.gz user@newhost:/backup/

# New host: restore
docker volume create postgres_data
docker run --rm \
  -v postgres_data:/data \
  -v /backup:/archive \
  alpine tar xzf /archive/postgres.tar.gz -C /data

Advantages:

  • Transfers all data and permissions
  • Independent of Docker versions
  • Works over any network (SCP, rsync, HTTPS)

🛠 Automation

Via cron on host

# /etc/crontabs/root - daily backup at 03:00
0 3 * * * docker run --rm -v postgres_data:/backup/data -v /opt/backup:/archive --entrypoint backup offen/docker-volume-backup:v2

Via Docker Compose

version: "3.8"
services:
  backup:
    image: offen/docker-volume-backup:v2
    container_name: volume-backup
    environment:
      BACKUP_CRON_EXPRESSION: "0 3 * * *"
      BACKUP_RETENTION_DAYS: "7"
    volumes:
      - postgres_data:/backup/postgres_data
      - redis_data:/backup/redis_data
      - /opt/backup:/archive
    entrypoint: ["/bin/sh", "-c", "backup"]

Features:

  • Built-in backup rotation
  • Logging inside container
  • S3-compatible storage support

📊 Integrity verification

# After backup: verify archive
tar -tzf backup-*.tar.gz | head -20
sha256sum backup-*.tar.gz > backup.sha256

# After restore: verify data
docker system df -v | grep postgres_data
docker logs postgres --tail 50

⚠️ Common issues

# "volume not found"
→ docker volume ls | grep <name>
→ docker volume inspect <name>

# "permission denied"
→ Run as root or with sudo
→ Check permissions: ls -la /opt/docker/backup/

# Backup too large
→ Exclude cache: tar --exclude='cache/*' ...
→ Configure rotation: BACKUP_RETENTION_DAYS=7

# Restore not working
→ Stop service: docker stop <container>
→ Check volume not in use: docker ps --filter volume=<name>

🗂 Checklist

Before backup

  • Checked space: df -h /opt/docker/backup
  • Stopped DB and critical services
  • Tested on one volume

Before restore

  • Stopped target containers
  • Verified archive: tar -tzf backup.tar.gz
  • Prepared rollback plan