[Gluster-devel] question on qemu gluster

[Bharata B Rao]

On Tue, Aug 21, 2012 at 8:53 AM, Yin Yin <maillistofyinyin at gmail.com> wrote:
> Hi, Bharata B Rao:
>    I've test your V5 qemu-gluster
> patch:http://lists.nongnu.org/archive/html/qemu-devel/2012-08/msg01023.html
>    The result is impressed!

Nice to know that you were able to use my patches.

>    but I've some question:
>    1. what's thre relation between qcow2 and gluster protocol?

In QEMU, gluster sits like an alternative to raw protocol. qcow2
driver and raw posix driver will be used in case of a normal qcow2
image. In case of a qcow2 image on a gluster volume, qcow2 driver and
gluster driver will be used.

But that shouldn't make any difference to the end user, qcow2 image on
a gluster volume should just work with my patches.

>        I can boot a vm in qcow2 format, but can't boot a vm that use another
> qcow2 disk as parent disk.

With my current patches (v6 + some additions), I am able to boot qcow2
image and also snapshot of a qcow2 image from gluster backend. This
should be true for v5, which you are using.

When you say "another qcow2 disk as parent disk", I assume you are
referring to a snapshot taken from a qcow2 base image ?

>    2. how does libvirt support gluster protocol?
>        add a VIR_DOMAIN_DISK_PROTOCOL_GLUSTER like
> VIR_DOMAIN_DISK_PROTOCOL_SHEEPDOG?

Yes. Harsh (on CC) is working on this and he will be posting the
patches to support GlusterFS from libvirt shortly.

Regards,
Bharata.