AWS RDS Replication – Multi-AZ vs. Read Replica

RDS Multi-AZ vs Read Replica
Multi-AZ deployments
RDS Multi-AZ deployment offers high availability, durability and failover support
RDS automatically provisioned and managed a synchronous standby instance at a different AZ (independent infrastructural in a physically distinct location).
RDS automatically switches to the standby, so that database operations can resume quickly and without administrative intervention in the event of Planned database maintenance.
Software patching
Rebooting the Primary instance
An instance of primary DB connectivity, host failure or connectivity to the primary DB instance
Failure of the Availability Zone
RDS maintains the same endpoint to the DB Instance even after a failover. This allows the application to resume database operation without manual intervention. Refer blog post @ RDSMulti-AZ deployment
RDS Read Replicas
In the event of an AZ failure, read replicas allow for increased scalability as well as greater database availability.
Read replicas allow for elastic scaling beyond the capacity constraints of a single DB instance to handle heavy database workloads.
RDS replicas can be multi-AZ (i.e. paired with standby instances in a different AZ.
By routing read queries from applications to a Read Replica, you can reduce the load on the source DB instance.
One or more replicas of a source DB Instance can be created to serve high-volume data read traffic from multiple copies. This increases aggregate read throughput. When necessary, read replicas can be promoted to become standalone DB Instances.
RDS uses DB engines’ built-in replication functionality. It creates a special type DB instance called a Read Replica. This is created from a source DB instance. It uses engines’ native asynchronous replica to update the read replication whenever there is a modification to the source DB instance.
RDS has read replicas for MySQL, MariaDB and PostgreSQL.
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You are open to further feedback, discussion, and correction. The reporting tier will aggregate user-generated data and publish status reports every thirty minutes. For the database tier, you are currently using a Multi-AZ RDS MySQL instance. ElastiCache is used as a database caching layer between your application tiers and the database tier. Please choose the answer that will allow your to implement the reporting layer with the least impact to your database.
Generate reports by querying Multi-AZ’s synchronously replicated standby RDS MySQL instance. (Standby instances cannot be used for scaling).
Create an RDS Read Replica that is connected to your MultiAZ master database. You can generate reports by querying this Read Replica.
You can generate the reports by querying ElastiCache’s database caching tier. A company is creating a two-tier web application in AWS. The company has limited staff and needs high availability.