[ 常見問題 ] Why is docker image eating up my disk space that is not used by docker

Source From Here 
Question 
I have setup docker and I have used completely different block device to store docker's system data: 

# cat /etc/sysconfig/docker

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1. # /etc/sysconfig/docker  
2. other_args="-H tcp://0.0.0.0:9367 -H unix:///var/run/docker.sock -g /disk1/docker"  

Note that /disk/1 is using a completely different hard drive /dev/xvdi. The problem is that when I continue download docker images and run docker containers, it seems that the other hard drive /dev/xvda1 is also used up. 

I can verify this problem by remove some docker images. After I removed some docker images, /dev/xvda1 has some more extra space now. 

How-To 
It's a kernel problem with devicemapper, which affects the RedHat family of OS (RedHat, Fedora, CentOS, and Amazon Linux). Deleted containers don't free up mapped disk space. This means that on the affected OSs you'll slowly run out of space as you start and restart containers. 

The Docker project is aware of this, and the kernel is supposedly fixed in upstream (https://github.com/docker/docker/issues/3182). 

A work-around of sorts is to give Docker its own volume to write to with option -g, --graph="/var/lib/docker" (Root of the Docker runtime) ("When Docker eats up you disk space"). This doesn't actually stop it from eating space, just from taking down other parts of your system after it does. 

My solution was to uninstall docker, then delete all its files, then reinstall: 

# sudo yum remove docker
# sudo rm -rf /var/lib/docker // Depending option -g.
# sudo yum install docker

This got my space back, but it's not much different than just launching a replacement instance. I have not found a nicer solution. 

Supplement 
* When Docker.io eats up your disc space 
* Docker document - daemon