[Gluster-users] Quorum in distributed-replicate volume

Dave Sherohman
Mon, 26 Feb 2018 11:15:35 -0000

I've configured 6 bricks as distributed-replicated with replica 2,
expecting that all active bricks would be usable so long as a quorum of
at least 4 live bricks is maintained.

However, I have just found

http://docs.gluster.org/en/latest/Administrator%20Guide/Split%20brain%20and%20ways%20to%20deal%20with%20it/

Which states that "In a replica 2 volume... If we set the client-quorum
option to auto, then the first brick must always be up, irrespective of
the status of the second brick. If only the second brick is up, the
subvolume becomes read-only."

Does this apply only to a two-brick replica 2 volume or does it apply to
all replica 2 volumes, even if they have, say, 6 bricks total?

If it does apply to distributed-replicated volumes with >2 bricks,
what's the reasoning for it?  I would expect that, if the cluster splits
into brick 1 by itself and bricks 2-3-4-5-6 still together, then brick 1
will recognize that it doesn't have volume-wide quorum and reject
writes, thus allowing brick 2 to remain authoritative and able to accept
writes.

--
Dave Sherohman