Docker Volume Management and Data Persistence

Why Volumes?

Container filesystems are ephemeral — when a container is removed, its data is lost. Docker volumes provide persistent storage that survives container restarts and removals.

Volume Types

Managing Volumes

# Create a named volume
docker volume create myapp-data

# List all volumes
docker volume ls

# Inspect a volume
docker volume inspect myapp-data

# Remove a volume
docker volume rm myapp-data

# Remove all unused volumes
docker volume prune

Using Volumes in Compose

services:
  postgres:
    image: postgres:16
    volumes:
      - pg-data:/var/lib/postgresql/data

  app:
    build: .
    volumes:
      - ./src:/app/src          # Bind mount for development
      - app-uploads:/app/uploads # Named volume for user uploads

volumes:
  pg-data:
  app-uploads:

Backup and Restore

# Backup a volume to a tar file
docker run --rm -v myapp-data:/data -v $(pwd):/backup alpine tar czf /backup/myapp-data.tar.gz -C /data .

# Restore from backup
docker run --rm -v myapp-data:/data -v $(pwd):/backup alpine sh -c "cd /data && tar xzf /backup/myapp-data.tar.gz"

Volume Drivers

Docker supports remote volume drivers for NFS, cloud storage, and distributed filesystems:

# NFS volume
docker volume create --driver local \
  --opt type=nfs \
  --opt o=addr=192.168.1.100,rw \
  --opt device=:/exported/path \
  nfs-data