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<p>First, sorry that my previous answer went directly to you and not
to the list. My mistake.</p>
<p>Well, detaching and attaching shared storage domains is not the
solution I was hoping for, but at least it gives me an option to
migrate VMs between hosts. It is either that or gluster (thanks,
Tony), depending on the performance impact.</p>
<p>Thanks for your help!<br>
</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">Eduardo Mayoral Jimeno (<a class="moz-txt-link-abbreviated" href="mailto:emayoral@arsys.es">emayoral@arsys.es</a>)
Administrador de sistemas. Departamento de Plataformas. Arsys internet.
+34 941 620 145 ext. 5153</pre>
<div class="moz-cite-prefix">On 30/04/18 14:48, Maor Lipchuk wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAJ1JNOf_KjTnOUCxTUbDsBGpc0e1sVJE2PaoqqvPV_OEWPXk1A@mail.gmail.com">
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<div>Will it help if you will have 2 local data centers?<br>
</div>
<div>and use the 'trick' with the detach/attach of the shared
storage domain?</div>
<div><br>
</div>
<div>Basically the architecture of oVirt does not relate
clusters to storage domains.</div>
<div>Storage domains are part of a data center while hosts are
part of a cluster which is part of a data center. I guess that
is the reason why it will be more problematic to declare
cluster as local.<br>
</div>
<div><br>
</div>
<div>Regards,</div>
<div>Maor</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Apr 30, 2018 at 3:23 PM,
Eduardo Mayoral <span dir="ltr"><<a
href="mailto:emayoral@arsys.es" target="_blank"
moz-do-not-send="true">emayoral@arsys.es</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>
<div class="h5"> On 30/04/18 14:05, Maor Lipchuk wrote:<br>
<blockquote type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Apr 30, 2018 at
2:01 PM, Eduardo Mayoral <span dir="ltr"><<a
href="mailto:emayoral@arsys.es"
target="_blank" moz-do-not-send="true">emayoral@arsys.es</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"><span>On
30/04/18 12:51, Tony Brian Albers wrote:<br>
> On 30/04/18 11:43, Eduardo Mayoral
wrote:<br>
>> Hi,<br>
>><br>
>> I would like to set up a new
oVirt deployment with hosts that have<br>
>> the VMs running on local attached
storage. I understand this has the<br>
>> requirement of having each host
in its own cluster (and own datacenter,<br>
>> it seems, I understand the need
for the dedicated cluster, not so much<br>
>> for the dedicated datacenter).<br>
>><br>
>> At the same time, I would
like to have some shared storage domains<br>
>> so I can use it to export VMs or
migrate them around hosts (probably in<br>
>> three stages, first migrate VM
storage from local to the shared storage<br>
>> domain, second migrate the host
(probably not possible to do a "hot"<br>
>> migration, but at least "cold"),
third migrate the VM storage from the<br>
>> shared storage domain to the
local storage domain of the new host).<br>
>><br>
>> So I thought maybe I can
deploy a datacenter in shared storage
mode,<br>
>> with one cluster per host. Use
one or two shared storage domains for<br>
>> master and as an stage area for
planned VM migrations as explained<br>
>> before, and then configure
several storage domains, one per host, as<br>
>> posix FS . I would then deploy
the VMs on the local posix FS storage<br>
>> domains and set affinity rules
for the VMs to their hosts as needed.<br>
>><br>
>> Would this work? Is there a
better way of achieving local storage<br>
>> and retaining the ability to
share storage among hosts and migrate VMs?<br>
>><br>
>><br>
> Have you thought about using
glusterfs? If hosts are physically close,
<br>
> that would probably be the best
solution.<br>
><br>
<br>
</span>Actually, yes, I also had glusterfs
in mind. However one of the main<br>
reasons to use local storage is performance,
and I am concerned about<br>
the write latencies of gluster (If using
gluster, I would handle things<br>
so the VM runs on one of the gluster nodes
hosting the VM data, so I<br>
assume the read latency will be close to the
one I would get with local<br>
storage, but the gluster replica(s) will be
on other hosts, so write<br>
latency may be significantly worse).<br>
<br>
Thanks a lot for the suggestion, it is a
good one, however, the original<br>
question stands: Would this work? Is there a
better way of achieving<br>
<span>local storage and retaining the
ability to share storage among hosts and<br>
migrate VMs?<br>
</span></blockquote>
<div><br>
</div>
<div>Hi Eduardo,</div>
<div>We support <span
style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">shared
storage domains in a local data center
since </span>oVirt 4.1.</div>
<div>Will this help you by any chance?</div>
</div>
</div>
</div>
</blockquote>
<br>
</div>
</div>
Hi, Moar,<br>
<br>
Thanks for your fast reply! This helps partly, but
does not quite solve my needs. If I understood correctly,
I can have a shared storage attached to a local storage
Data Center. However I cannot share a shared storage among
datacenters. I can detach the shared storage domain from
one datacenter and attach it to another one, but I cannot
"Share" the shared storage as in: both hosts see it at the
same time, as I would expect it to be the case with a
shared storage domain in a regular shared data center.<br>
<br>
Root of the problem for me actually is: I can totally
understand that host with local storage must "live" in a
dedicated cluster. But, why does it also need a dedicated
data center entity?<br>
<br>
Thanks for your help!<br>
<br>
--<br>
Eduardo Mayoral.<br>
<br>
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