Hi,

Today when using Redis Cluster, each and every published message will be broadcasted to every node in the cluster, making it pretty much unusable in large scale.

My request is to add a config option, something like cluster-pubsub-propagate that can be disabled so message will only be published within the same cluster node.
From my very little understanding, its only wrapping this line: https://github.com/antirez/redis/blob/unstable/src/pubsub.c#L320 in another if statement.

Once that will be done, it will be possible for clients to distribute message according to the already existing cluster slots and by that making sure messages go to the correct node.