Configuring and managing a Multi-AZ deployment

This page was generated from content adapted from the AWS Developer Guide

Multi-AZ DB instance deployments

• Note The high availability option isn't a scaling solution for read-only scenarios. You can't use a standby replica to serve read traffic. To serve read-only traffic, use a Multi-AZ DB cluster or a read replica instead. For more information about Multi-AZ DB clusters, see Multi-AZ DB cluster deployments. For more information about read replicas, see Working with DB instance read replicas.

• Important Using a snapshot to create the standby instance avoids downtime when you convert from Single-AZ to Multi-AZ, but you can experience a performance impact during and after converting to Multi-AZ. This impact can be significant for workloads that are sensitive to write latency. While this capability lets large volumes be restored from snapshots quickly, it can cause a significant increase in the latency of I/O operations because of the synchronous replication. This latency can impact your database performance. We highly recommend as a best practice not to perform Multi-AZ conversion on a production DB instance. To avoid the performance impact on the DB instance currently serving the sensitive workload, create a read replica and enable backups on the read replica. Convert the read replica to Multi-AZ, and run queries that load the data into the read replica's volumes (on both AZs). Then promote the read replica to be the primary DB instance. For more information, see Working with DB instance read replicas.

• Note You can force a failover manually when you reboot a DB instance. For more information, see Rebooting a DB instance.

• Note The default TTL can vary according to the version of your JVM and whether a security manager is installed. Many JVMs provide a default TTL less than 60 seconds. If you're using such a JVM and not using a security manager, you can ignore the rest of this topic. For more information on security managers in Oracle, see The security manager in the Oracle documentation.

Multi-AZ DB cluster deployments

• Important Multi-AZ DB clusters aren't the same as Aurora DB clusters. For information about Aurora DB clusters, see the Amazon Aurora User Guide.

• Important To prevent replication errors in RDS for MySQL Multi-AZ DB clusters, we strongly recommend that all tables have a primary key.

• Note The delay is shown in microseconds.

• Note The default TTL can vary according to the version of your JVM and whether a security manager is installed. Many JVMs provide a default TTL less than 60 seconds. If you're using such a JVM and not using a security manager, you can ignore the rest of this topic. For more information on security managers in Oracle, see The security manager in the Oracle documentation.