On 12/10/2015 08:35 PM, Chris Murphy wrote:
On Thu, Dec 10, 2015 at 11:47 AM, Jason Brooks
<jbrooks(a)redhat.com> wrote:
> You can ignore docker-storage-setup and edit /etc/sysconfig/docker-storage
> yourself.
OK I've done "systemctl disable docker-storage-setup"
>
> Here's what it looks like from the f23 vagrant box:
>
> DOCKER_STORAGE_OPTIONS=-s devicemapper --storage-opt dm.fs=xfs --storage-opt
dm.thinpooldev=/dev/mapper/atomicos-docker--pool --storage-opt
dm.use_deferred_removal=true
Short version: This works. Docker service starts, no errors, and it's
not using a loopback device.
Followup question: Does Docker directly use a thin pool without
creating (virtual size) logical volumes? Because I don't see any other
LV's created, and no XFS filesystem appears on the host using the
mount command. And yet I see XFS mount and umount kernel messages on
the host. This is sort of an esoteric question. However, I have no
access to container files from the host like I can see inside each
btrfs subvolume when btrfs is the backing method. And that suggests
possibly rather different backup strategies depending on the backing.
I believe it chops it up using low level device mapper stuff. I think
you don't see the mounts on your host because they are in a different
mount namespace (part of the magic behind containers).
For more info on docker + device mapper look at slides 37-44 of [1]
[1] -
http://www.slideshare.net/Docker/docker-storage-drivers