Must Know Features of Amazon RDS: Multi Availability Zones

Multi-AZ RDS deployments work by automatically provisioning a standby replica of your database in another availability zone within a region of your choice. Replicas are never created in any region other than the one you’ve chosen in order to keep the latency at a minimum and also due to compliance issues. RDS synchronously replicates the data to a standby replica, but keep in mind that a standby replica can’t serve read requests. Instead, they are used to provide data redundancy and minimize latency spikes during backups. If you need to offload heavy read traffic, consider RDS Read Replicas. This failover process for Multi-AZ deployments is used for most database engines running on RDS, including MySQL, PostgreSQL, MariaDB, and Oracle.

SQL Server, on the other hand, relies on Server Mirroring, while Amazon Aurora works a bit differently, something we’ll focus on later in the article. With Multi-AZ enabled, if the primary database becomes inaccessible (let’s say there was a hardware failure or some network problems), RDS performs a failover to a standby replica by retargeting the database endpoint. This process takes only a minute or two and requires no work on your end, allowing traffic to continue to flow automatically. One thing to consider when using Multi-AZ deployment is the performance implication on your database.

Compared to Single-AZ, it may increase latency for writing and committing due to the synchronous data replication occurring between the primary database and the standby replica. Also, if the failover does occur, you may have a slight change in latency as your traffic will move to and from a different AZ. You can enable Multi-AZ configuration both during the provisioning of the database, but also later by modifying it, in which case RDS takes a snapshot of the primary database and restores it into another availability zone. Keep in mind, though, that this can cause a significant performance impact, especially for larger databases, so plan ahead and make sure you enable this option during the provisioning of the database instance, if possible.

Features of Amazon RDS

When hosting data in the cloud, it is crucial that you can access it at the time or place of your choosing. Amazon RDS can provide high availability via a feature called Multi-AZ deployment, which maintains a redundant copy of your data in a separate location. The Multi-AZ service-level agreement guarantees a database uptime of at least 99.95 percent every month. Failovers can be processed with minimum latency through synchronous replication to a secondary database. 

Trying to scale an on-premise self-hosted database can be a serious challenge, but Amazon RDS makes it much simpler. Amazon RDS offers two different types of automatic scaling: horizontal (adding more machines) and vertical (adding more resources). The service comes equipped with a load balancer that can distribute requests evenly when the database is under increased demand.

The AWS suite of offerings includes extensive security measures like IAM (Identity and Access Management). Also, thanks to Amazon VPC (Virtual Private Cloud), you can isolate a particular database instance and connect to infrastructure with an encrypted VPN. 

Different types within the RDS engine may offer slightly different levels or kinds of security, but some things you can generally count on are automated patching and security monitoring. 

Amazon RDS includes a Performance Insights dashboard that makes it easier for users to analyze and troubleshoot the performance of their relational databases. Amazon CloudWatch allows users to better monitor performance and form metrics so you can get a clearer view of your business.