Nir,

The use cases of my current configuration is a mix of duplicated data clusters (Percona/Consul/CouchBase) and ephemeral systems (web servers) that work perfectly when 'locked' to a local host  These are built in such a way that losing a physical host reduces redundancy but isn't outwardly service degrading.  The other side is the duplicated databases (namely Percona) that would induce a fairly high level of NAS bandwidth that is avoided when they leverage the local storage on their host system.

The goal would be to have the ability to house the highly redundant and/or ephemeral systems to be housed on the hosts local storage, whereas guests that need HA or one-offs would be housed using the NAS allowing seamless HA or online migration.

On Fri, May 13, 2016 at 7:04 AM, Nir Soffer <nsoffer@redhat.com> wrote:
On Thu, May 12, 2016 at 5:50 AM, Jason Ziemba <jason@ziemba.net> wrote:
> I'm fairly new to oVirt (coming from ProxMox) and trying to wrap my head
> around the mixed (local/NAS) data domain options that are available.
>
> I'm trying to configure a set of systems to have local storage, as their
> primary data storage domain, though also want to have the ability to have a
> NAS based data domain for guests that are 'mobile' between hosts.  Currently
> I'm able to do one or the other, but not both (so it seems).
>
> When I put all of the systems in to a single cluster (or single data-center)
> I'm able to have the shared data domain, though have only found the ability
> to configure one system for local storage (not all of them).   When I split
> them out in to separate data centers, they all have their local data domain
> working, but only a single dc is able to access the shared data domain at a
> time.
>
> Am I missing something along the way (probably fairly obvious) that does
> exactly what I'm outlining, or is this functionality not available by
> design?

This is not available by design.

Can you explain the use case, why do you need to use local storage as
your primary data storage?

How are you going to migrate your vms if the primary storage is local?

How are you going to start the vms on another host after host failures,
if the vm storage is on the failed host, and the last state of that disk
is not available or even lost?

Nir