When Aurora was announced at AWS re:Invent 2014, many DBAs were skeptical. "Isn't this just MySQL put on a managed platform?" was the sentiment. It's not. Look inside Aurora and the story is completely different. Amazon dismantled the fundamental constraint of traditional relational DB architecture — that storage is bolted to a single server — into a shared distributed storage layer. The difference this decision makes explains "why Aurora, being the same MySQL, is faster and safer."
Traditional MySQL RDS (including Multi-AZ) looks like this. A single Primary instance writes data to a single EBS volume