AWS – New Multi-AZ deployment option for Amazon RDS for PostgreSQL and for MySQL; increased read capacity, lower and more consistent write transaction latency, and shorter failover time (Preview)
Amazon Relational Database Service (Amazon RDS) for MySQL and for PostgreSQL now supports a new Multi-AZ deployment option with one primary and two readable standby database instances. This deployment option optimizes write transactions and is ideal when your workloads require additional read capacity, lower write transaction latency, more resilience from network jitter (which impacts the consistency of write transaction latency), and high availability and durability.
Read More for the details.