[pgpool-general: 9183] Re: Pgpool-II 4.4.4 Split-brain situation

[Pradeep Prajapati]

Yes , I am using watchdog.
 Please refer the issue which I described in my previous email and guide.
Why the node 1 pgpool uses his outdated information to became primary again.

Regards,
Pradeep Prajapati

On Fri, 16 Aug, 2024, 3:02 pm Bo Peng, <pengbo at sraoss.co.jp> wrote:

> Hi,
>
> > Hello Team,
> >
> > I Need help or suggestions on the issue below pgpool-II.
> >
> > Example:-
> > Node1 -- Primary (Postgres & pgpool installed)
> > Node2 -- Standby (Postgres & pgpool installed)
> > Node3 -- Witness  (Pgpool installed)
> >
> > Incident:-
> >
> > 1. In the pgpool cluster we have node1 is primary, node2 is secondary,
> and
> > node3 is witness.
> > 2. node1 becomes unresponsive then failover is triggered and then node2
> > becomes the new primary.
> > 3. After 15 minutes node1 became responsive again and node1 is in primary
> > state and we have node 2 also in primary so a split brain situation
> > happened.
> > 4. Node 1 itself is decided as leader/coordinator based on the node 1
> > pgpool record and more number of connected standby nodes (based on old
> > state of information) , now i am the true leader, it is decided as the
> true
> > leader and asks node 2 to step down.
> > 5. In this case for 15 minutes data written to node 2 new primary after
> > node 1 responsive data gets started to return on node 1 again so here
> data
> > gets inconsistent.
> >
> > Please provide a suggestion in this case.
> >
> > NOTE:- We are using only for auto-failover not for auto-failback so
> > auto-failback is disabled.
>
> To avoid Split-brain, you can use watchdog by setting "use_watchdog = on".
> Are you using watchdog?
>
> --
> Bo Peng <pengbo at sraoss.co.jp>
> SRA OSS K.K.
> TEL: 03-5979-2701 FAX: 03-5979-2702
> URL: https://www.sraoss.co.jp/
>
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