[Gluster-users] Avoid Split-brain and other stuff

[Jeff Darcy]

On 11/16/2012 07:11 AM, John Mark Walker wrote:
> I think now is a good time to mention the quorum enhancements going into
> 3.4. I believe we'll have a way to determine quorum and resolve split-brain
> even in replica 2 setups. This will be possible via the creation of an
> arbiter node, which isn't a separate server, and whose sole job will be to
> determine quorum and determine the direction for self-heal.
> 
> I'll leave it to the devs to comment on how much is implemented now and
> whether it's in the master branch.

I wrote about this recently on the HekaFS blog.

	http://hekafs.org/index.php/2012/11/different-forms-of-quorum/

The current status is that a very weak form of quorum (within a replica set
with an ugly tie-break if N=2) is in 3.3 and master already.  There's a patch
to add server-side quorum enforcement.

	http://review.gluster.org/#change,3811 (master)
	http://review.gluster.org/#change,3817 (3.3)

These are still in review.  Also, as mentioned in my article, I think it needs
to be further enhanced in a couple of ways.  To sum up, I think we know the way
forward on this issue but it's taking us a while to get there.