<p dir="ltr">I do not think a quorum feature does a fair job in a 2 way replication. The minimum criteria to use quorum is 3 and it does not make any sense to me to turn it on by default for 2 way replication especially when HA is not achieved if the 1st brick the pair goes down.</p>
<p dir="ltr">BTW, whats the history behind this limitation?</p>
<p dir="ltr">-Atin<br>
Sent from one plus one</p>
<div class="gmail_quote">On 04-Mar-2016 6:00 pm, "Pranith Kumar Karampuri" <<a href="mailto:pkarampu@redhat.com">pkarampu@redhat.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
<br>
On 03/04/2016 05:47 PM, Bipin Kunal wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
HI Pranith,<br>
<br>
Thanks for starting this mail thread.<br>
<br>
Looking from a user perspective most important is to get a "good copy"<br>
of data. I agree that people use replication for HA but having stale<br>
data with HA will not have any value.<br>
So I will suggest to make auto quorum as default configuration even<br>
for 2-way replication.<br>
<br>
If user is willing to lose data at the cost of HA, he always have<br>
option disable it. But default preference should be data and its<br>
integrity.<br>
</blockquote>
<br>
That is the point. There is an illusion of choice between Data integrity and HA. But we are not *really* giving HA, are we? HA will be there only if second brick in the replica pair goes down. In your typical deployment, we can't really give any guarantees about what brick will go down when. So I am not sure if we can consider it as HA. But I would love to hear what others have to say about this as well. If majority of users say they need it to be auto, you will definitely see a patch :-).<br>
<br>
Pranith<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Thanks,<br>
Bipin Kunal<br>
<br>
On Fri, Mar 4, 2016 at 5:43 PM, Ravishankar N <<a href="mailto:ravishankar@redhat.com" target="_blank">ravishankar@redhat.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 03/04/2016 05:26 PM, Pranith Kumar Karampuri wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
hi,<br>
So far default quorum for 2-way replication is 'none' (i.e.<br>
files/directories may go into split-brain) and for 3-way replication and<br>
arbiter based replication it is 'auto' (files/directories won't go into<br>
split-brain). There are requests to make default as 'auto' for 2-way<br>
replication as well. The line of reasoning is that people value data<br>
integrity (files not going into split-brain) more than HA (operation of<br>
mount even when bricks go down). And admins should explicitly change it to<br>
'none' when they are fine with split-brains in 2-way replication. We were<br>
wondering if you have any inputs about what is a sane default for 2-way<br>
replication.<br>
<br>
I like the default to be 'none'. Reason: If we have 'auto' as quorum for<br>
2-way replication and first brick dies, there is no HA.<br>
</blockquote>
<br>
<br>
+1. Quorum does not make sense when there are only 2 parties. There is no<br>
majority voting. Arbiter volumes are a better option.<br>
If someone wants some background, please see 'Client quorum' and 'Replica 2<br>
and Replica 3 volumes' section of<br>
<a href="http://gluster.readthedocs.org/en/latest/Administrator%20Guide/arbiter-volumes-and-quorum/" rel="noreferrer" target="_blank">http://gluster.readthedocs.org/en/latest/Administrator%20Guide/arbiter-volumes-and-quorum/</a><br>
<br>
-Ravi<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
If users are fine with it, it is better to use plain distribute volume<br>
rather than replication with quorum as 'auto'. What are your thoughts on the<br>
matter? Please guide us in the right direction.<br>
<br>
Pranith<br>
</blockquote>
<br>
<br>
</blockquote></blockquote>
<br>
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