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Re: CEPH / CloudStack features


On 07/27/2018 12:18 PM, Dag Sonstebo wrote:
> Hi all,
> I’m trying to find out more about CEPH compatibility with CloudStack / KVM – i.e. trying to put together a feature matrix of what works  and what doesn’t compared to NFS (or other block storage platforms).
> There’s not a lot of up to date information on this – the configuration guide on [1] is all I’ve located so far apart from a couple of one-liners in the official documentation.
> Could I get some feedback from the Ceph users in the community?

Yes! So, at first, Ceph is KVM-only. Other hypervisors do not support
RBD (RADOS Block Device) from Ceph.

What is supported:

- Thin provisioning
- Discard / fstrim (Requires VirtIO-SCSI)
- Volume cloning
- Snapshots
- Disk I/O throttling (done by libvirt)

Meaning, when a template is deployed for the first time in a Primary
Storage it's written to Ceph and all other Instances afterwards are a
clone of that primary image.

You can snapshot a RBD image and then have it copied to Secondary
Storage. Now, I'm not sure if keeping the snapshot in Primary Storage
and reverting works yet, I haven't looked at that in recent times.

The snapshotting part on Primary Storage is probably something that
needs some love and attention, but otherwise I think all other features
are supported.

I would recommend a CentOS 7 or Ubuntu 16.04/18.04 hypervisor, both work
just fine with Ceph.


> Regards,
> Dag Sonstebo
> [1] http://docs.ceph.com/docs/master/rbd/rbd-cloudstack/
> Dag.Sonstebo@xxxxxxxxxxxxx 
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