[DRBD-user] Re: How to avoid split brain in primary/primary configuration

Florian Haas florian.haas at linbit.com
Tue Mar 18 09:53:26 CET 2008

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


On Monday 17 March 2008 17:04:46 Grégory Steulet wrote:
> Hi Florian,
> We are currently working on a DRBD presentation for a technical event. Now
> I'm trying to deal with split brain problem in a primary/primary
> configuration. I read your article about dopd, which is actually working
> fine in a primary/secondary configuration. Unfortunately for the moment I
> didn't find a way to avoid split-brain in primary/primary configuration
> when the network connection between nodes is cut.

I have suggested a possible solution for this here:


Unfortunately the original poster has not yet come back with any feedback on 
this. I guess it's a good idea to be a little patient. :-)

> I'm looking for an handler or anything which can make something like a "two
> phase commit" (maybe a protocol D) ;-). I mean if the primary cannot write
> on the other primary he either refuses to write or switch in  secondary
> mode.

This "either write to both nodes or none at all" is a concept that we refer to 
as a write quorum, and this is a future DRBD feature listed on the internal 
development roadmap. There is no release date for this yet, but it will be 
included within this DRBD major release (i.e. before DRBD 9).

> Second question, is-it possible to set up a resource to use two ethernet
> interfaces (like in heartbeat ;-) ) ?

No. But you can run DRBD over bonded network interfaces.

> By the way... your blog was really helpful !

Glad to hear that. :-)


: Florian G. Haas
: LINBIT Information Technologies GmbH
: Vivenotgasse 48, A-1120 Vienna, Austria

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