docker-storage-setup

If you install docker-1.7 ( or later ) then you will get with it docker-storage-script delivered

# rpm -q docker
docker-1.7.0-3.el7.x86_64
#rpm -ql docker | grep storage
/etc/sysconfig/docker-storage
/usr/bin/docker-storage-setup
/usr/lib/docker-storage-setup/docker-storage-setup
/usr/lib/systemd/system/docker-storage-setup.service
/usr/share/man/man1/docker-storage-setup.1.gz

/usr/bin/docker-storage-setup is responsible for docker storage configuration, it is shell script and if you open and read it, you can get all what it does from there.

docker-storage-setup will follow instructions in /usr/lib/docker-storage-setup/docker-storage-setup and configure docker storage backend based on parameters there. In most cases you are fine with defaults, but you can change them if you want.

In case you decide to step away from default values ( eg, to give volume group name you like, or to specify block devices you want to use… ) then it is possible too. All you need to do is to

cp /usr/lib/docker-storage-setup/docker-storage-setup /etc/sysconfig

Edit, /etc/sysconfig/docker-storage-setup

and start docker

systemctl start docker

In docker-storage-setup, interesting values are

DEVS – list of block devices to be used for docker storage
VG – volume group name
CHUNK_SIZE – default is 512K

Pay attention on CHUNK_SIZE – value of 512K is showed as most efficient from storage backend performance point of view. Check Determine the default optimal chunk/block size for docker workload and Adjust default chunksize on thinp volume created by docker-storage-setup

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