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<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I believe this is unquestionably a valid concern, but I believe there is a way to configure around it (those who know watchdog better
will provide details, I’m sure). However, there’s still the problem that, having only one primary, if the corp link is down, half of the app can’t see across regions to a primary database…so you have a 50% or so outage instead of a full outage.
<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Again, I’d take a close look at Postgres-BDR…this is exactly the types of scenarios that it’s designed to handle.
<o:p></o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Best of luck!<o:p></o:p></span></span></p>
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<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><b><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666">David Sisk</span></b></span><span style="mso-bookmark:_MailEndCompose"><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666"><o:p></o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666">Engineer - Software<o:p></o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"></span><a href="mailto:dsisk@cisco.com"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666;text-decoration:none">dsisk@cisco.com</span></span></a><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p></o:p></span></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666">Tel:
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<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><b><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666">Cisco Systems, Inc.<o:p></o:p></span></b></span></p>
<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:8.5pt;font-family:"Arial",sans-serif;color:#666666">7025-6 Kit Creek Road PO Box 14987<br>
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<p class="MsoNormal"><span style="mso-bookmark:_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> pgpool-general-bounces@pgpool.net [mailto:pgpool-general-bounces@pgpool.net]
<b>On Behalf Of </b>Yates, James C. -ND<br>
<b>Sent:</b> Tuesday, December 20, 2016 12:25 PM<br>
<b>To:</b> Muhammad Usama <m.usama@gmail.com><br>
<b>Cc:</b> Muhammad Usama <muhammad.usama@enterprisedb.com>; pgpool-general@pgpool.net<br>
<b>Subject:</b> [pgpool-general: 5186] Re: Architecture Questions<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Dec 20, 2016, at 6:27 AM, Muhammad Usama <<a href="mailto:m.usama@gmail.com">m.usama@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Hi</span>
<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Can you please explain a little more about your concerns of the split-brain situation you want to avoid?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">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.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">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?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Thanks<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Best regards<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Muhammad Usama<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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