You have a misconception about CockroachDB and YugabyteDB architecture. It is not 2-way replication. It writes to a Raft group. The transaction can be picked up by any node because the transaction intents are also replicated. The main difference with RAC is that the current version of a row is read/write on the Raft Leader, replicated to followers (that can be elected new leader). In RAC, the block with current version of a row is moved back and forth between the instance. That's possible only with reliable, short distance, dedicated network. Distributed SQL can scale out to multiple availability zones. Not RAC