Docker uses root partition, might need more storage space

Installation
9

Another solution on OS level can be to mount /var/lib/docker on a dedicated partition.

To do this, please, stop Docker, make sure that no process accesses /var/lib/docker and do the following:

Provide an additional volume. In this example it is /dev/sdx8.
Format it accordingly, i.e.

mkfs.xfs -n ftype=1 /dev/sdx8

or

mkfs.ext4 /dev/sdx8

etc.

If it fails in mkfs.xfs you might run a newer version of mkfs.xfs which has ftype=1 already as default. Just issue

mkfs.xfs /dev/sdx8

Stop Docker.

service docker stop

Make sure the directory is not used anymore:

lsof | grep /var/lib/docker

Prepare directories and mount the new volume:

mv /var/lib/docker /var/lib/__docker
mkdir /var/lib/docker
mount /dev/sdx8 /var/lib/docker

Move all contents there to:

rsync -aH /var/lib/__docker/ /var/lib/docker
# mind the trailing slash. It takes care to copy the whole tree to the right position.

Don’t forget to add /dev/sdx8 to /etc/fstab.

Remove the old directory if everything is fine.

rm -rf /var/lib/__docker
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