<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Dec 20, 2016 at 10:24 PM, Yates, James C. -ND <span dir="ltr">&lt;<a href="mailto:James.C.Yates.-ND@disney.com" target="_blank">James.C.Yates.-ND@disney.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">



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What I’m concerned about is the corporate network link between the AWS regions going down and PgPool doing a failover.  Then I could have the East and West region both think they have a master and doing updates/inserts on each.  Then when the link comes back
 up, my databases are out of sync and I could lose data. </div></blockquote><div><br></div><div>Yes, This is a valid point. Earlier I thought you were concerned about the Watchdog going into the split-brain which is not likely to happen especially in the active-active watchdog configurations.</div><div>Unfortunately, I can&#39;t think of any perfect solution for backend failover in case of a network partitioning between East and West regions at the moment, Can you please explain the availability requirements of your application, Like when the regions are isolated from each other, is it okay as per the requirements that the region that does not have the primary PostgreSQL keeps offline until the link is restored?</div><div><br></div><div>Regards</div><div>Muhammad Usama</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><span class=""><br>
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<div>On Dec 20, 2016, at 6:27 AM, Muhammad Usama &lt;<a href="mailto:m.usama@gmail.com" target="_blank">m.usama@gmail.com</a>&gt; wrote:</div>
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Can you please explain a little more about your concerns of the split-brain situation you want to avoid?</div>
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As far as I understand from the architecture diagram the proposed deployment consists of four PostgreSQL servers (Two in each AWS availability zone) and the Pgpool-II servers in front of each PostgreSQL. And the Application servers can connect to any of the
 four available Pgpool-II, So this seems like an active-active Pgpool-II configuration. Which means you would not be using the floating-IP (delegate IP) with the Pgpool-II.</div>
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So if this is correct and you are not planing to use the floating IP and master-standby configuration of Pgpool-II, What worries you about the split-brain?</div>
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Thanks</div>
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Best regards</div>
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Muhammad Usama</div>
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