Open Stack

We've running it both ways. We have clouds with dedicated storage nodes, and clouds sharing storage/compute.

The storage/compute solution with ceph is working ok for us. But, that particular cloud is 1gigabit only and seems very slow compared to our other clouds. But because of the gigabit interconnect, while the others are 40gigabit, its not clear if its slow because of the storage/compute together, or simply because of the slower interconnect. Could be some of both.

I'd be very curious if anyone else had a feeling for storage/compute together on a faster interconnect.

Thanks,
Kevin

________________________________________
From: Jesse Keating [jlk at bluebox.net]
Sent: Thursday, March 19, 2015 9:20 AM
To: openstack-operators at lists.openstack.org
Subject: Re: [Openstack-operators] Hyper-converged OpenStack with Ceph

On 3/19/15 9:08 AM, Jared Cook wrote:
> Hi, I'm starting to see a number of vendors push hyper-converged
> OpenStack solutions where compute and Ceph OSD nodes are one in the
> same.  In addition, Ceph monitors are placed on OpenStack controller
> nodes in these architectures.
>
> Recommendations I have read in the past have been to keep these things
> separate, but some vendors are now saying that this actually works out
> OK in practice.
>
> The biggest concern I have is that the compute node functions will
> compete with Ceph functions, and one over utilized node will slow down
> the entire Ceph cluster, which will slow down the entire cloud.  Is this
> an unfounded concern?
>
> Does anyone have experience running in this mode?  Experience at scale?
>
>

Not CEPH related, but it's a known tradeoff that compute resource on
control nodes can cause resource competition. This is a tradeoff for the
total cost of the cluster and the expected use case. If the use case
plans to scale out to many compute nodes, we suggest upgrading to
dedicated control nodes. This is higher cost, but somewhat necessary for
matching performance to capacity.

We may start small, but we can scale up to match the (growing) needs.


--
-jlk

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