On Feb 12, 2016, at 8:34 AM, Ravishankar N <ravishankar at redhat.com>
wrote:> Consistency, availability, tolerance to network partitions. You get to pick
any two.
I wanted the first two. I did not get them. By default, we get split brain.
This means no consistency. To cure that, we choose quorums. But when the first
of a replica 2 pair goes away, you then loose write access. Without write, we
loose availability. So, if you think it is possible, let me know how to
reconfigure my array and I will tell you if it worked. If you could update the
docs to explain how you get the first two, that would be nice. If you could
update the docs to state that the array goes into a partial read-only state if a
replica pair goes away, that would be nice.
I?m fine with running in a degraded state when a server goes away. When it
comes back, I want it to suck down all the new changes from the authoritative
replica pair known to the quorum and then once it has all the data, then it can
be marked as not-degraded and resume normal operation.
I want each node to notice a down server, and when it is part of a 51%
partition, I want the remaining replica members of that server to become
degraded replica N-1 set. When the server comes back up, and want it to repair
back into a replica N state.