Amazon RDS for SQL Server now supports Multi-AZ in the AWS Asia Pacific (Osaka) Region. This new high availability option leverages SQL Server Database Mirroring (DBM) or Always On Availability Groups (AGs) technology. Multi-AZ helps you meet the requirements of enterprise-grade production workloads running on SQL Server. The Multi-AZ deployment option provides enhanced availability and data durability by automatically replicating database updates between two AWS Availability Zones. Availability Zones are physically separate locations with independent infrastructure engineered to be insulated from failures in other Availability Zones.
Source:: Amazon AWS