[pgpool-general: 5187] Re: Architecture Questions

David Sisk -X (dsisk - TEKSYSTEMS INC at Cisco) dsisk at cisco.com
Wed Dec 21 04:09:49 JST 2016

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.

Again, I’d take a close look at Postgres-BDR…this is exactly the types of scenarios that it’s designed to handle.

Best of luck!


David Sisk
Engineer - Software
dsisk at cisco.com<mailto:dsisk at cisco.com>

Cisco Systems, Inc.
7025-6 Kit Creek Road PO Box 14987
United States

[http://www.cisco.com/assets/swa/img/thinkbeforeyouprint.gif]Think before you print.

This email may contain confidential and privileged material for the sole use of the intended recipient. Any review, use, distribution or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive for the recipient), please contact the sender by reply email and delete all copies of this message.
Please click here<http://www.cisco.com/web/about/doing_business/legal/cri/index.html> for Company Registration Information.

From: pgpool-general-bounces at pgpool.net [mailto:pgpool-general-bounces at pgpool.net] On Behalf Of Yates, James C. -ND
Sent: Tuesday, December 20, 2016 12:25 PM
To: Muhammad Usama <m.usama at gmail.com>
Cc: Muhammad Usama <muhammad.usama at enterprisedb.com>; pgpool-general at pgpool.net
Subject: [pgpool-general: 5186] Re: Architecture Questions

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.

On Dec 20, 2016, at 6:27 AM, Muhammad Usama <m.usama at gmail.com<mailto:m.usama at gmail.com>> wrote:


Can you please explain a little more about your concerns of the split-brain situation you want to avoid?

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.

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?

Best regards
Muhammad Usama

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20161220/2b93f584/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image003.png
Type: image/png
Size: 121724 bytes
Desc: image003.png
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20161220/2b93f584/attachment-0002.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image004.png
Type: image/png
Size: 1469 bytes
Desc: image004.png
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20161220/2b93f584/attachment-0003.png>

More information about the pgpool-general mailing list