On 1/3/13 5:26 PM, Yonik Seeley wrote:
I agree - it's pointless to have two replicas of the same shard on a
single node. But I'm talking about having replicationFactor as a
target, so when you start up *new* nodes they will become a replica
for any shard where the number of replicas is currently less than the
replicationFactor. Ideally, one would be able to create a new
collection with no nodes initially assigned to it if desired.
Yes THAT is a cool thing, as I also mentioned earlier. We should
implement that!
But as it is today, if e.g. you have 2 nodes and ask for
replicationFactor 3 you will get 2 replica on one node and 1 replica on
the other. Here I would rather only create 1 replica on each node, so
that you only start up with 2 replica all in all (even though you asked
for 3). Then "remember" (in ZK) that you actually asked for 3 and let
the overseer create the 3rd replica on a new node as soon as such an
additional node is available.
