[Users] glusterfs and ovirt

[Bharata B Rao]

On Wed, May 16, 2012 at 3:29 PM, Itamar Heim <iheim at redhat.com> wrote:
> On 05/15/2012 07:35 PM, Andrei Vakhnin wrote:
>>
>> Yair
>>
>> Thanks for an update. Can I have KVM hypervisors also function as storage
>> nodes for glusterfs? What is a release date for glusterfs support? We're
>> looking for a production deployment in June. Thanks
>
>
> current status is
> 1. patches for provisioning gluster clusters and volumes via ovirt are in
> review, trying to cover this feature set [1].
> I'm not sure if all of them will make the ovirt 3.1 version which is slated
> to branch for stabilization June 1st, but i think "enough" is there.
> so i'd start trying current upstream version to help find issues blocking
> you, and following on them during june as we stabilize ovirt 3.1 for release
> (planned for end of june).
>
> 2. you should be able to use same hosts for both gluster and virt, but there
> is no special logic/handling for this yet (i.e., trying and providing
> feedback would help improve this mode).
> I would suggest start from separate clusters though first, and only later
> trying the joint mode.
>
> 3. creating a storage domain on top of gluster:
> - expose NFS on top of it, and consume as a normal nfs storage domain
> - use posixfs storage domain with gluster mount semantics
> - future: probably native gluster storage domain, up to native
>  integration with qemu

I am looking at GlusterFS integration with QEMU which involves adding
GlusterFS as block backend in QEMU. This will involve QEMU talking to
gluster directly via libglusterfs bypassing FUSE. I could specify a
volume file and the VM image directly on QEMU command line to boot
from the VM image that resides on a gluster volume.

Eg: qemu -drive file=client.vol:/Fedora.img,format=gluster

In this example, Fedora.img is being served by gluster and client.vol
would have client-side translators specified.

I am not sure if this use case would be served if GlusterFS is
integrated as posixfs storage domain in VDSM. Posixfs would involve
normal FUSE mount and QEMU would be required to work with images from
FUSE mount path ?

With QEMU supporting GlusterFS backend natively, further optimizations
are possible in case of gluster volume being local to the host node.
In this case, one could provide QEMU with a simple volume file that
would not contain client or server xlators, but instead just the posix
xlator. This would lead to most optimal IO path that bypasses RPC
calls.

So do you think, this use case (QEMU supporting GlusterFS backend
natively and using volume file to specify the needed translators)
warrants a specialized storage domain type for GlusterFS in VDSM ?

Regards,
Bharata.
-- 
http://bharata.sulekha.com/blog/posts.htm, http://raobharata.wordpress.com/