Re: Experiences with Ceph at the June'14 issue of USENIX ;login:

[Constantinos Venetsanopoulos <cven@grnet.gr>]

Hello Robin,

On 6/3/14, 24:40 AM, Robin H. Johnson wrote:
> On Mon, Jun 02, 2014 at 09:32:19PM +0300,  Filippos Giannakos wrote:
>> As you may already know, we have been using Ceph for quite some time now to back
>> the ~okeanos [1] public cloud service, which is powered by Synnefo [2].
> (Background info for other readers: Synnefo is a cloud layer on top of
> Ganeti).
>
>> In the article we describe our storage needs, how we use Ceph and how it has
>> worked so far. I hope you enjoy reading it.
> Are you just using the existing kernel RBD mapping for Ganeti running
> KVM, or did you implement the pieces for Ganeti to use the QEMU
> userspace RBD driver?

Non of the above. From the Ceph project we are just using RADOS,
which we access via an Archipelago [1] backend driver that uses
librados from userspace.

We integrate Archipelago with Ganeti with the Archipelago ExtStorage
provider.

> I've got both Ceph & Ganeti clusters already, but am reluctant to marry
> the two sets of functionality because the kernel RBD driver still seemed
> to perform so much worse than the Qemu userspace RBD driver, and Ganeti
> still hasn't implemented the userspace mapping pieces :-(
>

Ganeti supports accessing RADOS from userspace (via the qemu-rbd
driver) since version 2.10. The current stable is 2.11. Not only that,
but starting v2.13 (not released yet), you will be able to configure the
access method per-disk, e.g. saying that the first disk of the instance
will be kernel backed and the second userspace backed. So, I'd suggest
you give it a try and see how it goes :)

Thanks,
Constantinos


[1] https://www.synnefo.org/docs/archipelago/latest/