Amazon RDS Multi-AZ

Highly available, durable relational databases deployed across up to three Availability Zones (AZs)

Amazon RDS Multi-AZ with one standby

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.
Amazon RDS Multi-AZ deployment How It Works Diagram

Amazon RDS Multi-AZ with two readable standbys

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 a choice of AWS Graviton2– or Intel–based instances for compute.

Introduction to Amazon RDS Multi-AZ

Amazon RDS Multi-AZ deployments provide enhanced availability and durability for your Amazon RDS database (DB) instances, making them a natural fit for production database workloads. With two different deployment options, you can customize your workloads for the availability they need.

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 PostgreSQL
  • Amazon RDS for MySQL
  • Amazon RDS for MariaDB
  • Amazon RDS for SQL Server
  • Amazon RDS for Oracle
  • Amazon RDS for Db2
  • Amazon RDS for PostgreSQL
  • Amazon RDS for MySQL
  • Amazon RDS for MariaDB
  • Amazon RDS for SQL Server
  • Amazon RDS for Oracle
  • Amazon RDS for Db2
  • 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
Minor version upgrades downtime
  • When using Automatic Minor Version Upgrades, minor version upgrade downtime occurs during the Amazon RDS 30-minute maintenance window
  • When using Automatic Minor Version Upgrades, minor version upgrade downtime occurs during the Amazon RDS 30-minute maintenance window
  • Typically under 1 second when customers add an open source or Amazon RDS Proxy to their deployment
  • Typically under 35 seconds with Multi-AZ with two readable standbys alone

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
  • Access to Dedicated Log Volumes
  • Uses local storage for transactional logs to reduce jitter

Customers

  • SysCloud

    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. With the new Amazon RDS Multi-AZ deployment option, we expect to create a better experience for our customers.

    Vikram Srinivasan, Director, Infrastructure at SysCloud

Pricing

Amazon RDS Multi-AZ is available for RDS for PostgreSQLRDS for MySQLRDS for MariaDBRDS for SQL ServerRDS for Oracle, and RDS for Db2. Amazon RDS Multi-AZ with two readable standbys is available for RDS for PostgreSQL and RDS for MySQL. To learn how Amazon Aurora provides enhanced availability by making your data durable across three Availability Zones, see Multi-AZ deployments with Aurora Replicas.

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. 

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