<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<p>RAID 6 doesn't make exactly 3 copies of data.</p>
<p>I think storage is too expensive when compared to the total cost
of the platform that 3 copies is waste of storage or luxury, given
than if you have a permanent failure you still can make a new 2nd
copy of the data provided you have storage left for that.</p>
<br>
<div class="moz-cite-prefix">On 25/04/2017 10:26, Donny Davis wrote:<br>
</div>
<blockquote
cite="mid:CAMHmko9FfZQErKCyg7crth-ZJode9qWC5DgdjcbM7EirVRUHrA@mail.gmail.com"
type="cite">
<div dir="ltr">I personally want three copies of my data, more
akin to RAID 6(ish) so in my case replica 3 makes perfect
sense. </div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Apr 24, 2017 at 11:34 AM, Denis
Chaplygin <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:dchaplyg@redhat.com" target="_blank">dchaplyg@redhat.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">Hello!<br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Apr 24, 2017 at 5:08
PM, FERNANDO FREDIANI <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:fernando.frediani@upx.com"
target="_blank">fernando.frediani@upx.com</a>></span>
wrote:<br>
<blockquote style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"
class="gmail_quote">
<div bgcolor="#FFFFFF">
<p>Hi Denis, understood.<br>
What if in the case of adding a fourth host to
the running cluster, will the copy of data be
kept only twice in any of the 4 servers ?</p>
</div>
</blockquote>
<div><br>
</div>
<div>replica volumes can be build only from 2 or 3
bricks. There is no way to make a replica volume
from a 4 bricks. <br>
<br>
</div>
<div>But you may combine distributed volumes and
replica volumes [1]:<br>
<br>
<pre><code class="m_4650192000417937643gmail-hljs m_4650192000417937643gmail-sql">gluster volume <span class="m_4650192000417937643gmail-hljs-operator"><span class="m_4650192000417937643gmail-hljs-keyword">create</span> test-volume replica <span class="m_4650192000417937643gmail-hljs-number">2</span> transport tcp server1:/b1 server2:/b2 server3:/b3 server4:/b4</span></code></pre>
test-volume would be like a RAID10 - you will have
two replica volumes b1+b2 and b3+b4 combined into a
single distributed volume. In that case you will<br>
have only two copies of your data. Part of your data
will be stored twice on b1 and b2 and another one
part will be stored twice at b3 and b4<br>
You will be able to extend that distributed volume
by adding new replicas.<br>
<br>
</div>
<div><br>
[1] <a moz-do-not-send="true"
href="https://gluster.readthedocs.io/en/latest/Administrator%20Guide/Setting%20Up%20Volumes/#creating-distributed-replicated-volumes"
target="_blank">https://gluster.readthedocs.<wbr>io/en/latest/Administrator%<wbr>20Guide/Setting%20Up%<wbr>20Volumes/#creating-<wbr>distributed-replicated-volumes</a><br>
</div>
</div>
</div>
</div>
<br>
______________________________<wbr>_________________<br>
Users mailing list<br>
<a moz-do-not-send="true" href="mailto:Users@ovirt.org">Users@ovirt.org</a><br>
<a moz-do-not-send="true"
href="http://lists.ovirt.org/mailman/listinfo/users"
rel="noreferrer" target="_blank">http://lists.ovirt.org/<wbr>mailman/listinfo/users</a><br>
<br>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</body>
</html>