Amazon RDS Multi-AZ with one standby

Automatic fail over Protect database performance Enhance durability Increase availability 
Support high availability for your application with automatic database failover that completes as quickly as 60 seconds with zero data loss and no manual intervention.
Avoid suspending I/O activity on your primary during backup by backing up from your standby instance.
Use Amazon RDS Multi-AZ synchronous replication technologies to keep data on your standby database instance up to date with the primary. Enhance availability by deploying a standby instance in a second AZ, and achieve fault tolerance in the event of an AZ or database instance failure.

How it works

In an Amazon RDS Multi-AZ deployment, Amazon RDS automatically creates a primary database (DB) instance and synchronously replicates the data to an instance in a different AZ. When it detects a failure, Amazon RDS automatically fails over to a standby instance without manual intervention.
product-page-diagram_MAZ_HIW@2x

Amazon RDS Multi-AZ with two readable standbys

Automatically fail in over typically under 35 seconds Maximize performance and scalability by splitting read and write Gain up to 2x faster transaction commit latency Increase read capacity
Automatically failover in typically under 35 seconds with zero data loss and with no manual intervention. Route queries to write servers and appropriate read replica standby instances to maximize performance and scalability.  Achieve up to 2x improved write latency compared to Multi-AZ with one standby. Gain read scalability by distributing traffic across two readable standby instances.

How it works

Deploy highly available, durable MySQL or PostgreSQL databases in three AZs using Amazon RDS Multi-AZ with two readable standbys. Gain automatic failovers in typically under 35 seconds, up to 2x faster transaction commit latency compared to Amazon RDS Multi-AZ with one standby, additional read capacity, and storage backed by AWS Graviton2–based instances.
product-page-diagram_TAZ_HIW@2x

Amazon Aurora

Automatically failover in quickly as 5 seconds  Optimize performance with up to 15 read replicas Maximize durability

Achieve 99.99% availability 

Automatically failover as quickly as 5 seconds during an instance failure and avoid downtime Ensure peak performance and optimize read capacity by replicating data to one of up to 15 low-latency read replicas Secure data during failures or the loss of an AZ with an SSD-backed virtualized storage layer that replicates data six ways across three AZs  Safeguard your database availability with up to 99.99% uptime each monthly billing cycle

How it works

Amazon Aurora employs an SSD-backed virtualized storage layer that automatically replicas your storage six ways across three AZs, handling loss of up to two copies of data without affecting write availability and up to three copies without affecting read availability.
product-page-diagram_TAZ_HIW@2x

Comparison Table

Amazon RDS Single-AZ or Amazon RDS Multi-AZ with one standby or Amazon RDS Multi-AZ with two readable standbys

Feature

Single-AZ

Multi-AZ with one standby

Multi-AZ with two readable standbys

Available engines

  • Amazon RDS for MariaDB
  • Amazon RDS for MySQL
  • Amazon RDS for PostgreSQL
  • Amazon RDS for Oracle
  • Amazon RDS for SQL Server
  • Amazon RDS for MariaDB
  • Amazon RDS for MySQL
  • Amazon RDS for PostgreSQL
  • Amazon RDS for Oracle
  • Amazon RDS for SQL Server
  • Amazon RDS for PostgreSQL
  • Amazon RDS for MySQL

Additional Read
capacity

  • None: the read capacity is limited to your primary
  • None: Your standby DB instance is only a passive failover target for high availability
  • Two standby DB instances act as failover targets and serve read traffic
  • Read capacity is determined by the overhead of write transactions from the primary

·        

Lower latency (higher throughput) for transaction commits

 

 

  • Up to 2x faster transaction commits compared to Amazon RDS Multi-AZ with one standby

Automatic failover duration

  • Not available: a user, a user-initiated point-in-time-restore operation will be required.
  • This operation can take several hours to complete
  • Any data updates that occurred after the latest restorable time (typically within the last 5 minutes) will not be available
  • A new primary is available to serve your new workload in as quickly as 60 seconds
  • Failover time is independent of write throughput
  • A new primary is available to serve your new workload in typically under 35 seconds
  • Failover time depends on length of replica lag

Higher resiliency to AZ outage

  • None: in the event of an AZ failure, your risk data loss and hours of failover time
  • In the event of an AZ failure, your workload will automatically failover to the up-to-date standby
  • In the event of a failure, one of the two remaining standbys will takeover and serve the workload (writes) from the primary

Lower jitter for transaction commits

  • No optimization for jitter
  • Sensitive to impairments on the write path
  • Uses the 2-of-3 write quorum: insensitive to up to one impaired write path

Customers

SysCloud creates automatic backups for critical software as a service (SaaS) applications, monitors for malicious files, and delivers powerful insights about your data and compliance —all from one dashboard. SysCloud uses Amazon RDS Multi-AZ with two readable standbys for its internal monitoring system: “The new Amazon RDS Multi-AZ deployment option offers us a cost-efficient way to achieve better performance, availability, and read scalability,” said Vikram Srinivasan, Director, Infrastructure at SysCloud. “With the new Amazon RDS Multi-AZ deployment option, we expect to create a better experience for our customers.”

Pricing

Amazon RDS Multi-AZ is available for Amazon RDS for MariaDB, Amazon RDS for MySQL, Amazon RDS for PostgreSQL, Amazon RDS for Oracle, and Amazon RDS for SQL Server. Amazon RDS Multi-AZ with two readable standbys is available for RDS for MySQL and RDS for PostgreSQL. To learn about how Amazon Aurora provides enhanced availability by automatically replicating storage six ways across three availability zones, see Amazon Aurora.

For Single-AZ deployments, Multi-AZ deployments with one standby instance, and Multi-AZ deployments with two readable standbys, pricing is per DB instance-hour consumed, from the time a DB instance is launched until it is stopped or deleted. Partial DB instance-hours are billed in one-second increments with a 10 minute minimum charge following a billable status change such as creating, starting, or modifying the DB instance class.

For more information on pricing for Amazon RDS Multi-AZ, see the Amazon RDS pricing pages. 

Learn more about Amazon RDS features
Learn with 10-minute tutorials

Explore Amazon RDS with simple tutorials.

Explore hands-on training 
Sign up for an AWS account
Start building with Amazon RDS and Amazon Aurora

Dig into the Amazon RDS User Guide to get started.

Read the documentation 
Start building with Amazon RDS in the console
Dive Deep on Amazon RDS Multi-AZ

Dive deep into how Amazon RDS Multi-AZ works and the different deployment options.

Watch the session