[DRBD-user] Dual-primary split-brain recovery after reboot

Lars Ellenberg lars.ellenberg at linbit.com
Fri Jun 24 20:43:51 CEST 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Fri, Jun 24, 2011 at 12:10:14PM -0600, Pete Ashdown wrote:
> On 06/24/2011 11:38 AM, Lars Ellenberg wrote:
> >> Thanks, I actually did read that in the User's Guide, but where I'm
> >> confused is that the Ubuntu 10.04 init script has this line in it:
> >>
> >>     $DRBDADM sh-b-pri all # Become primary if configured
> >>
> >> So if that is there, is all that I need is to insert a "$DRBDADM secondary
> >> all" in the stop section?
> > Certainly not.
> > I dare say the DRBD init script is fine ;-)
> >
> > There was something about the correct _order_ of actions
> > in my original reply.
> >
> > If you stop things in the wrong order,
> > then that will lead to what is known as "DRBD split brain".
> >
> > Of course, if after reboot, you start things in the wrong order,
> > like promoting to Primary before connecting to the peer,
> > that will do the same.
> >
> > You need to get the *order* of the start and stop actions right.
> Is getting the order of the start/stop actions the responsibility of an
> init script? Is the Ubuntu start/stop sequence numbering wrong?  All I'm
> trying to do is have recovery automatic after a reboot, because once clvm
> and kvm get running on top of drbd, it is a lot harder to recover.

I understand that you "just want it to work".

One might think that the order in which init starts and stops things
should usually be "correct".

However, apparently thing do not work, for you.

I told you what needs to happen to
get rid of the symptoms you complain about.

Now you,
as in

 ==> You <==

need to figure out (in detail), what are the things that actually happen.
And where do they diverge from the things that should happen.

Once you know that, you can either fix it yourself,
(and kindly tell the list what the problem was).
Or come back here with that additional information,
and ask for further assistance, and we will try to help fixing it, and
possibly even find out why it "went wrong" in the first place.

But without that further information (about what, exactly, in which
order, actually happens), well, I'm sorry, but "I want to be a virtuoso
pianist, just tell me which menu item to click..." is the wrong question


: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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