Open Stack

On 12/7/2016 9:25 AM, Jonathan Proulx wrote:
>
> We've been using Ceph as ephemeral backend (and glance store and
> cinder backend) for > 2 years (maybe 3 ) and have been very happy.
>
> cinder has been rock solid on RBD side. Early on when we had 6 osd
> servers we lost one in production to a memory error.  1/6 is a large
> fraction to loose but Ceph handled it as designed and there was not
> noticable impact to any running instances.
>
> The ability to start VMs from snap shot of a glance image (which is
> how it's implemented if glance and nova are both cinder backed) makes
> start up super fast.
>
> Having shared storage also make live migration easy so we can do
> hardware maintenence (kernel and OS upgrades) without impacting
> running VMs
>
> As of Mitaka snapshotting running VMs is also fast, though for
> earlier releases VMs we suspended while the running RBD volumes was
> copied down to the the hypervisors and then restarted while the
> downloaded images was re-uploaded from the hypervisor to glance and
> back into Ceph.  This could mean VMs down foro 15min or more if they
> had large root volumes.  As I said this got fixed in Mitaka so if
> you're current this is no longer a problem.
>

This is the specific change mentioned above:

https://review.openstack.org/#/c/205282/

-- 

Thanks,

Matt Riedemann