Yes, correct. However, this is something which could be implemented in 
Infinispan, ie. configure a mode (DIST_SYNC_ASYNC ?) where the primary 
owner of a key is updated synchronously and the other(s) asynchronously. 
Apart from data center replication, this might even be a nice feature to 
have in Infinispan proper ?

Maybe this is something we can add in Infinispan. I.e., with node 

hints (https://jira.jboss.org/browse/ISPN-180) (*) we could detect 

which recipients are local and which are remote, and accordingly split 

the RPC into 2: a sync local RPC and an async remote RPC.

+1