Can we suggests single-AZ RDS for AlwaysoN configured databases


Hi All,

We are migrating the databases to RDS instance where on-premises configured with Alway on. we suggested to configure the Multi-AZ for production servers but Single-AZ is providing 99% SLA and application required the 99%. The Single-AZ and application SLA are same so , Can we configure the Single-AZ instead of multi-AZ.



1 Answer
Accepted Answer

Multi AZ or Single AZ comes down to your risk appetite.

If you require Always on high availability then you should use MultiAZ. The SLA may be 99.9 but you should plan depending on your RPO RTO.

In the event of an AZ issue or issue with the primary database, do you require an alternative failover instance? There wouldn’t be any guarantee how long an outage may occur. Your primary RDS instance may be caught in a AZ fire or some natural event. It’s down to your risk and requirements and what ifs?

You may want to plan for the worse and hope for the best.

Multi AZ high availability is part of the AWS well architected framework both

  1. Operational Excellence
  2. Reliability
profile picture
answered 2 months ago
profile picture
reviewed 10 days ago
reviewed 2 months ago
  • Hi Gary, Agreed with you. Can you please help me where I can find the RDS single-AZ RPO and RTO.

    I think RDS backup will saved in different region so we can restore databases/RDS if any case some thing happened to RDS region.

  • The RPO and RTO is something that you will need to define within your organisation regarding your own data and application. RDS Snapshot underlying storage is techincally S3 but thats performed daily. AWS Backup is designed to use the AWS global infrastructure to replicate your backups across multiple Availability Zones for durability of 99.999999999% (11 nines) in any given year, provided that you adhere to the current AWS Backup documentation.

    How often will you be backing up the database as this would form part of your RPO

  • We have enabled the AWS automatic backups. RDS snapshot will be taken by every day and every 5 minutes log backup will happens for RDS SQL Server. Thanks for your feedback.

  • Ensure you test this scenario and that it works as expected.

  • apologies for late replay . Sure , Thanks

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions