Does Amazon's RDS Multi-AZ deployment cost twice as much as the normal cost of a single instance?

Question

It's not totally clear based on Amazon's provided documentation. Intuitively, it feels like it'd cost twice as much as a normal RDS instance for a two-zone deployment; does anyone here have experience with this, and could confirm or disconfirm that?

Answer 1

Amazon's RDS pricing page has two sections. One for Single-AZ Deployment and one for Multi-AZ Deployment.

Yes, Multi-AZ is about twice the price of Single-AZ. For example I see:

• db.t2.micro single - $0.017/hour
• db.t2.micro multi - $0.034/hour

Answer 2

To estimate the RDS cost I recommend the AWS Simple Monthly Calculator.

For a db.m4.large PostgreSQL instance I get the following:

• Single-AZ - $140.13/month - no High Availability
• Multi-AZ - $280.25/month

This means: Single-AZ cost = ½ Multi-AZ cost

Below two screenshots:

Single-AZ

Multi-AZ

PS: no data transfer costs, no additional backup costs included

Answer 3

TLDR: Yes it does Kent.

It costs twice as much. Because it's two instances.