6.4: When to use one or the other? (Dev vs Prod)

Now that we’ve explored the two methods for persisting data inDocker— Bind Mounts and Named Volumes — it’s important to know which method to use depending on the context.

The choice depends primarily on the environment and the level of control you want over your files

Bind Mounts: direct access, rapid development

A Bind Mount is perfect when you want to:

• Access files directly from your host machine.
• Quickly debug or modify application files.
• Work on local development or a temporary project.

Typical example:

-v ./data:/var/lib/mysql

Key benefits:

• Immediate access to files from the host
• Perfect for debugging and testing
• Easy backup of local files

Limitations:

• Less portable: the local path must exist on every machine
• Risk of permission issues depending on the system
• Less secure data (stored directly on the host)

Named Volumes:Docker managed, stable production

Named Volumes are preferable when you want to:

• LetDocker the system manage data storage.
• Ensure persistence even after containers are deleted or updated.
• Have a portable and secure solution for production.

Typical example:

-v my_data:/var/www/html

Key benefits:

• Persistent even after the container is deleted
• Automatic management by Docker
• More secure and portable for production

Main limitation:

• Direct file access is less convenient: you must go throughDockerthe CLI or a temporary container

Practical comparison

🧠 Key takeaway

• Bind Mounts provide direct access to files and are convenient for development.
• Named Volumes offer more secure and portable persistence, ideal for production.
• DockerUnderstanding this distinction helps prevent data loss and ensures your projects are properly structured.
• Always be careful with destructive commands like docker-compose down -v.

The most important thing is to never store important data solely inside the container:Docker is designed so that containers are ephemeral.

            +--------------------------+
            |      MACHINE HÔTE        |
            +--------------------------+
            |                          |
            |  ./data (Bind Mount)     |       my_data (Named Volume)
            |      +-------+           |       +----------------+
            |      | Fichier|           |       | Gestion Docker |
            |      +-------+           |       | volume interne |
            |                          |       +----------------+
            +------------+-------------+
                         |
                         ▼
            +--------------------------+
            |      CONTENEUR           |
            +--------------------------+
            |                          |
            | /var/lib/mysql           |       /var/www/html
            |  (Bind Mount)            |       (Named Volume)
            |                          |
            +--------------------------+

Explanation of the diagram

1. Bind Mount (./data:/var/lib/mysql)
   • ./dataThe container writes directly to the local folder.
   • The files are immediately visible on the host.
   • Ideal for development, debugging, and quick testing.
2. Named Volume (my_data:/var/www/html)
   • my_dataDocker Creates and manages a named volume.
   • Data is persistent, even if the container is deleted.
   • More portable and secure, ideal for production.