[Pacemaker] Split-brain on DRBD + Corosync/Pacemaker

[Felipe Gutierrez]

Hi Digimer,

I am already using crm-fence-peer.sh

resource r8 {
handlers {
    fence-peer "/usr/lib/drbd/crm-fence-peer.sh";
    after-resync-target "/usr/lib/drbd/crm-unfence-peer.sh";
    split-brain "/usr/lib/drbd/notify-split-brain.sh root";
}

Is Stonith still necessary? How do I configure it? I tried once but My
machine couldn't reboot because stonith process was blocking and I give up
to use it.

Thanks
Felipe

On Wed, Dec 19, 2012 at 3:43 PM, Digimer <lists at alteeve.ca> wrote:

> On 12/19/2012 06:21 AM, Felipe Gutierrez wrote:
> > Hi everyone,
> >
> > I have a scenario that I disconnect my primary from the network and the
> > secondary assume, becaming primary. After this, I connect the younger
> > primary, and both nodes became secondary(DRBD), or Slave on Pacemaker.
> > It is because DRBD on younger Primary is Standalone and Outdated. It is
> > a split-brain scenario.
> > How do I make to my Pacemaker take care of that?
> > I read these
> >
> http://www.drbd.org/users-guide-8.3/s-split-brain-notification-and-recovery.html
> > ,
> >
> http://www.drbd.org/users-guide-8.3/s-configure-split-brain-behavior.html#s-automatic-split-brain-recovery-configuration
> > and I think I cannot configure only my DRBD resource. I believe I need
> > to do something on my Pacemaker.
> > I think Stonith is not a good idea too, because I can reconnect my
> > younger primary machine.
> >
> > Thanks in advance,
> > Felipe
>
> Stonith isn't just a good idea, it's required for safe operation.
>
> The moment that the two DRBD nodes are Primary and StandAlone, you have
> a split-brain. Stonith protects against this by tell drbd to block and
> call a fence against the lost peer when connection breaks. When the
> fence succeeds, the surviving node knows that it's peer can't be Primary
> anymore because it's been killed.
>
> If you are using Pacemaker, tell DRBD to use the 'crm-fence-peer.sh'
> script. If you are using red hat cluster, use 'obliterate-peer.sh' or
> 'rhcs_fence'. In either case, this "hooks" DRBD into pacemaker or cman's
> existing fence devices.
>
> --
> Digimer
> Papers and Projects: https://alteeve.ca/w/
> What if the cure for cancer is trapped in the mind of a person without
> access to education?
>



-- 
*--
-- Felipe Oliveira Gutierrez
-- Felipe.o.Gutierrez at gmail.com
-- https://sites.google.com/site/lipe82/Home/diaadia*
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