As you use Docker daily, you may notice that it begins to take up significant disk space over time. Containers, images, volumes, and build caches can accumulate and clog up your disk, leading to performance issues or even running out of space.

Why Disk Space Builds Up with Docker

Whenever you run or build Docker containers, it creates images, volumes, and other related files. These are useful when you actively use the container, but they can become irrelevant after a while. Cleaning up this unused data not only helps optimize your system but also ensures Docker performs smoothly without any bottlenecks.

Let’s dive into how to recover disk space.

1. Removing All Unused Docker Data

If you want a quick, all-in-one cleanup solution, Docker provides a command that purges all unused containers, images, volumes, and even the build cache. This command is perfect for reclaiming a significant amount of space.

Before you run it, make sure to stop any containers you don’t need because the command will remove everything that’s not actively in use.

docker system prune --all

What does this do?

• Stops and removes containers that are not running.

• Deletes unused images that are no longer needed for any container.

• Cleans up volumes that are not attached to any container.

• Removes build caches, which are temporary files created during the container build process.

Note: This process may take some time, especially when clearing up large build caches. Be patient as Docker works through the cleanup.

2. Targeted Cleanup Options

If you don’t want to remove everything, Docker allows you to clean specific parts of the system—like images, volumes, or containers—individually.

a. Removing Unused Docker Images

Docker images that are no longer used by any containers can pile up over time, consuming space.

docker image prune --all

This command only deletes unused images, so you won’t have to worry about losing images tied to any running container.

b. Removing Unused Docker Volumes

Volumes can store persistent data generated by containers, but once a container is removed, the volume may no longer serve a purpose. To clean them up:

docker volume prune --all

This ensures you only keep volumes that are currently linked to active containers.

c. Removing Unused Docker Containers

If you’re only looking to remove containers that are stopped or inactive, Docker provides a command for that too:

docker container prune --all

This is a safer option if you want to focus solely on removing containers without touching images or volumes.

Real-Life Example: How Much Space Can You Reclaim?

When I first ran these commands, I was shocked by how much space I recovered. By running the full docker system prune --all command, I reclaimed 86 GB of disk space!

Depending on your Docker usage, your results may vary, but the difference can be significant.

Hope you found this guide helpful! 😊