How to Free Disk Space with docker system prune

To free Docker disk space, run docker system df to see what uses space, then docker system prune to remove stopped containers, unused networks, dangling images and unused build cache. Add -a to also remove every image no container uses. Volumes are kept unless you add --volumes. Large container logs in /var/lib/docker/containers need log rotation instead.

Difficulty	Time	Works on	Needs
Beginner	10 minutes	Any Linux server with Docker Engine	Docker access (`docker` group or sudo)

Before you start

Run the commands as a user in the docker group, or put sudo in front.
Prune means “delete what nothing is using”. Each prune command asks for confirmation unless you add -f.
If the disk is already 100% full and Docker won’t respond, see fix “No space left on device” first.

How to see what Docker uses

docker system df

TYPE            TOTAL     ACTIVE    SIZE      RECLAIMABLE
Images          12        3         6.8GB     5.1GB (75%)
Containers      5         3         120MB     40MB (33%)
Local Volumes   6         3         2.4GB     900MB (37%)
Build Cache     48        0         3.2GB     3.2GB

RECLAIMABLE is what prune can free. For a per-image, per-container and per-volume list, run docker system df -v. docker system df does not count container logs. Check those and the total with:

sudo du -sh /var/lib/docker
sudo du -sh /var/lib/docker/containers/*/*-json.log | sort -h | tail -5

What does each prune command remove?

Command	Removes	Safe?
`docker container prune`	All stopped containers	Yes, if you don’t need them
`docker image prune`	Dangling images (untagged layers left after updates)	Yes
`docker image prune -a`	Every image no container uses	Yes, but images are downloaded again when needed
`docker builder prune`	Unused build cache	Yes; the next build is slower
`docker network prune`	Networks no container uses	Yes
`docker volume prune`	Unused anonymous volumes	Check first
`docker volume prune -a`	All unused volumes, including named ones	Deletes data
`docker system prune`	Stopped containers, unused networks, dangling images, unused build cache	Yes
`docker system prune -a`	The same, plus all unused images	Yes
`docker system prune --volumes`	The same, plus unused anonymous volumes	Check first

How to clean up Docker safely

Check what is running

docker ps -a

Start any container you want to keep that is currently stopped, so its image and data count as in use.

Remove unused data

docker system prune -a

Type y to confirm. The command ends with Total reclaimed space:.

Review volumes before deleting them

docker volume ls -f dangling=true

These volumes are not attached to any container. Delete one you are sure about with docker volume rm <name>.

Check the result

docker system df
df -h /

docker volume prune -a, docker system prune --volumes and docker compose down -v delete volume data, such as databases and uploads. After docker compose down, that project’s volumes count as unused. Back up before removing volumes.

How to stop container logs filling the disk

By default the json-file log driver keeps logs without a size limit.

Set log rotation for all new containers

Create or edit /etc/docker/daemon.json:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  }
}

This keeps at most three 10 MB log files per container.

Restart Docker

sudo systemctl restart docker

Running containers stop during the restart. Containers with a restart policy start again on their own.

Recreate existing containers

The setting applies only to containers created afterwards. Recreate yours, for example with docker compose up -d --force-recreate in each Compose project.

To empty one large log straight away without stopping the container:

sudo truncate -s 0 "$(docker inspect --format='{{.LogPath}}' web)"

Replace web with the container name. The old log lines are gone after this.

How to prune Docker automatically

Run a weekly clean-up of anything unused for more than 7 days. Open root’s crontab with sudo crontab -e and add:

0 4 * * 0 docker system prune -af --filter "until=168h" > /dev/null 2>&1

This runs every Sunday at 04:00 and never touches volumes. See schedule tasks with cron.

Frequently asked questions

Does docker system prune delete my running containers?

No. It removes only stopped containers and data that no container uses. Running containers, their images and their volumes stay.

Why is /var/lib/docker still large after pruning?

Usually it is container logs, volumes or images that running containers use. Check logs with the du command above and volumes with docker system df -v.

Is it safe to delete files in /var/lib/docker by hand?

No. Deleting files there can corrupt Docker. Use the prune and rm commands, or truncate for log files only.

Can I move Docker’s data to a bigger disk?

Yes, set data-root in /etc/docker/daemon.json to a folder on the new disk and restart Docker; move the existing data first or Docker starts empty. See mount a new disk and manage VPS storage.

VPS and dedicated server guides

Every guide in this section.

Find what is using disk space

Track down large folders.

Fix No space left on device

When the disk is already full.

Docker commands cheat sheet

Containers, images and volumes.

Check disk space

df and du explained.

Checked against the official Docker pruning documentation and json-file log driver docs on 4 November 2026; prune, df, log truncation and daemon.json tested on Ubuntu 24.04 LTS with Docker Engine 29.9.2. Commands can differ between Docker versions.

Need Extra Help?

If you encounter any issues, our support team is ready to assist:

Live Chat: Quick assistance via our website.
Support Ticket: Open a Ticket
Discord: Join our Community
Email: support@freakhosting.com

Save on Your Hosting

Ready to upgrade your hosting? Use code KB20 at checkout for 20% off your first order!

Last Updated: November 2026

Start here

Connect to your server

Linux basics

Linux security

Networking

Web servers & websites

Databases

Docker & self-hosting

Backups & storage

Performance & monitoring

Linux troubleshooting

Windows Server basics

Windows Server security & networking

Windows Server troubleshooting

Account & notifications

How to Free Disk Space with docker system prune

Before you start

How to see what Docker uses

What does each prune command remove?

How to clean up Docker safely

How to stop container logs filling the disk

How to prune Docker automatically

Frequently asked questions

Does docker system prune delete my running containers?

Why is /var/lib/docker still large after pruning?

Is it safe to delete files in /var/lib/docker by hand?

Can I move Docker’s data to a bigger disk?

VPS and dedicated server guides

Find what is using disk space

Fix No space left on device

Docker commands cheat sheet

Check disk space

Need Extra Help?

Save on Your Hosting

​Before you start

​How to see what Docker uses

​What does each prune command remove?

​How to clean up Docker safely

​How to stop container logs filling the disk

​How to prune Docker automatically

​Frequently asked questions

​Does docker system prune delete my running containers?

​Why is /var/lib/docker still large after pruning?

​Is it safe to delete files in /var/lib/docker by hand?

​Can I move Docker’s data to a bigger disk?

​Related guides

VPS and dedicated server guides

Find what is using disk space

Fix No space left on device

Docker commands cheat sheet

Check disk space

​Need Extra Help?

​Save on Your Hosting

Before you start

How to see what Docker uses

What does each prune command remove?

How to clean up Docker safely

How to stop container logs filling the disk

How to prune Docker automatically

Frequently asked questions

Does docker system prune delete my running containers?

Why is /var/lib/docker still large after pruning?

Is it safe to delete files in /var/lib/docker by hand?

Can I move Docker’s data to a bigger disk?

Related guides

Need Extra Help?

Save on Your Hosting