Right now, this extension does reads/writes from any datacenter, and uses redis as a backing store. It also relies on redis persistence to some extent. This usage blocks Luca's proposal of simplifying out twemproxy setup for redis.
Right now, we have two sockets on each apache, one that talks to the local redis pool and the other to the remote datacenter pool. Each listens on a socket with a DC-specific name (though mediawiki-config hides this a bit). The idea of having just one socket for the local pool would simplifiy the setup and the original reason for them had to do with a way of using redis for session that we no longer plan on using (instead, dynamo or cassandra are contenders).
Perhaps this can be switched to another store (like dynamo over redis). It could act as an canary use case to test dyanmo. This would handle locality and replication.