Hello,

Currently I am in process of rewriting and unifying old JGroups based 
messaging mechanisms in an application to akka based solution.

For now akka-cluster will be used as a mechanism to know about currently 
available nodes by listening to MemberEvent and ReachabilityEvent, based on 
those events mechanism similar to DistributedPubSub will deliver messages 
to subscribed recipients from different nodes. The thing I am interested in 
is the current (2.3.13) state of network/partitions handling.

As far as I know (I am not an expert on JGroups) if there will be some kind 
of network partition/temporary node failure the nodes will happily work 
along and when everything goes back to normal nodes will reform single 
cluster and shared cluster state will be merged (in my situation it is 
trivial - application does not use this feature of JGroups). This state of 
affairs is OK for in my case - even if there is a partition between nodes 
(nodes A,B do not see nodes C,D) some of the operations can be performed 
without the need to contact nodes in other partition. Now I am interested 
in possible differences between JGroups and akka-cluster behaviour in 
failure scenarios.

If I assume that:


   1. I will have auto-down-unreachable-after=off
   2. I will not use remote deployment/remote death watch 
   3. the actors one one node know about others by using actorSelection 
   based on known path and node addresses from cluster events 

then can I assume that:

   1. no system will be put to quarantined state (no "system" messages)
   2. actors inside the partitions can still send messages to themselves 
   normally, if I will try to send message to actor ref from unreachable node 
   the message will simply be not delivered (and optionally logged as 
   dead-letter)
   3. when network partition heals up all members will form single cluster 
   by sending each other gossip messages and unmarking unreachable nodes
   4. in situation when some node is restarted ungracefully - remote actor 
   system does not use leave method - when new incarnation of old ActorSystem 
   connects old one will be automatically marked as down without the need of 
   issuing manual down command thanks 
   to https://github.com/akka/akka/issues/16726


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