Article about docker using btrfs filesystem
Intro#
So dockers tend to start growing like weeds. And cost me space i don’t have. But one could change the storage driver. You could choose LVM and take advantage of the snapshots or btrfs which i already have.
Btrfs#
Btrfs is a next generation copy-on-write filesystem that supports many advanced storage technologies that make it a good fit for Docker. Btrfs is included in the mainline Linux kernel.
Docker’s btrfs storage driver leverages many Btrfs features for image and container management. Among these features are block-level operations, thin provisioning, copy-on-write snapshots, and ease of administration. You can easily combine multiple physical block devices into a single Btrfs filesystem.
Requirements#
- Install btrfs
- Make sure you have a volume formatted as btrfs (not part of the article)
Clean all dockers and images#
# Delete all containers
sudo docker rm $(sudo docker ps -a -q)
# Delete all images
sudo docker rmi $(sudo docker images -q)
Setup#
Make sure you have btrfs on your system
sudo cat /proc/filesystems | grep btrfs
- Stop docker
sudo service docker stop
- Create a backup of you docker settings
sudo mv /var/lib/docker/ /var/lib/docker.bak
- create a subvolume from an existing btrfs FS
btrfs subvolume create /archive/dockers
NOTE: It’s better to use a dedicate disk for it
- Create the symlink
ln -s /archive/dockers /var/lib/docker
- Copy the backup data to the new location
cp -rp /var/lib/docker.bak/* /var/lib/docker/
- Configure Docker to use the btrfs storage driver. This is required even though
/var/lib/docker/is now using a Btrfs filesystem. Edit or create the file/etc/docker/daemon.json.
{
"storage-driver": "btrfs"
}
- Start docker service
sudo service docker start
- Check if docker is running with docker support
sudo docker info|grep "Storage Driver"
You could check the volumes being created with the command
sudo btrfs subvolume list /var/liv/docker |grep dockers