Amazon RDS Reserved Instances give you the option to make a low, one-time payment for each DB instance you want to reserve and in turn receive a significant discount on the hourly charge for that instance. Amazon RDS provides three RDS Reserved Instance types (Light, Medium, and Heavy Utilization Reserved Instances) that enable you to balance the amount you pay upfront with your effective hourly price. They are available for all MySQL, Oracle and SQL Server database engines. Based on your application workload and the amount of time you plan to run them, Amazon RDS Reserved Instances may provide substantial savings over running on-demand DB instances.
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Reserved Instances are available in three different types: Light, Medium, and Heavy Utilization.
Reserved Instances can save you up to 76% over On-Demand rates when used in steady state.
Reserved Instances are easy to use and require no change to how you use Amazon RDS. When computing your bill, our system will automatically apply Reserved Instance rates first to minimize your costs. An instance hour will only be charged at the On-Demand rate when the total number of instances you run that hour exceeds the number of applicable Reserved Instances you own.
Reserved Instances can be purchased for one or three year terms.
Reserved Instances are available in all the AWS regions.
Reserved Instances are available for all supported DB Engines.
Reserved Instance Types
There are three Reserved Instance types (RIs) shown below that enable you to balance the amount you pay upfront with your effective hourly price:
Light Utilization RIs – – Light Utilization RIs offer the lowest upfront payment of all of the RI types. Along with this low upfront payment, you’ll receive a significantly discounted hourly usage fee. Light Utilization RIs allow you to turn off your DB Instance at any point and not pay the hourly fee. Light Utilization RIs are ideal for DB Instances with sporadic usage. For example, development and test instances that run for about seven to twelve hours a day or the instances used for short term projects (e.g. consulting engagements or usability studies) and run for 3-7 months in a year. Using Light Utilization Reserved DB Instances, you can save up to 51% for a 1-year term and 63% for a 3-year term when compared to running the same DB instance on an On-Demand basis.
Medium Utilization RIs – Medium Utilization RIs have a higher upfront payment than Light Utilization RIs, but a much lower hourly usage fee. These are the exact same RIs that Amazon RDS has offered for the last few years. Medium Utilization RIs allow you to turn off your DB Instance at any point and not pay the hourly fee. They are best suited for workloads that run most of the time, but have some variability in usage. Using Medium Utilization RIs, you can save up to 57% for a 1-year term and 71% for a 3-year term when compared to running the same DB instance on an On-Demand basis.
Heavy Utilization RIs – Heavy Utilization RIs offer the most absolute savings of any Reserved Instance type. Most production applications require database servers to be available 24×7. Heavy Utilization RIs are most appropriate for your steady-state production workloads that will be always running, so you commit to the entire duration of the Reserved Instance term. With this RI, you pay a higher upfront payment than Medium Utilization RIs and the lowest hourly usage fee. You are charged this low hourly rate for every hour in the Reserved Instance term you purchase. Using Heavy Utilization RIs, you can save up to 61% for a 1-year term and 76% for a 3-year term when compared to running the same DB instance on an On-Demand basis.
Reserved Instances are a great option for a number of different use cases.
Steady State Usage
Most production applications require database servers to be available 24×7. Reserved Instances could provide your business substantial savings if you exclusively use On-Demand DB Instances for your production applications. Heavy Utilization RIs offer the largest discounts for steady state workloads. If you expect your DB Instance to be running most of the time but value the flexibility of being able to turn off your instances at any point, Medium Utilization RIs may be the right choice for you.
Reserved Instances could also provide significant cost savings for mission critical applications that run on Multi-AZ database deployments for higher availability and data durability.
You can determine whether Reserved or On-Demand DB Instances best fit your needs by comparing On-Demand hourly rates and the effective hourly rate of Reserved Instances. In order to calculate an effective hourly rate, amortize the one-time fee over the term and add the hourly usage rate. At steady state usage, the effective hourly rate for 1 year term Heavy Utilization Reserved Instances are as much as 53% lower than On-Demand rates, and the 3 Year term Heavy Utilization Reserved Instances can be as much as 76% lower than On-Demand rates. For Medium Utilization Reserved Instances with steady state usage, 1 year reservations are as much as 57% lower and 3 year reservations are as much as 71% lower than corresponding On-Demand rates.
Low to Medium Annual Utilization
Reserved Instances can also provide significant cost savings even if your databases run less than 100% of the time. Unlike traditional dedicated capacity, Reserved Instances allow you to avoid usage charges when you don’t need the instance. If your workload requires a database to run for 3-7 months in a year (e.g. scaling up the number of DB instances during peak season for your business), a 1 year term Light Utilization RI allows you to minimize your RDS bill.
The table below shows the possible savings over On-Demand rates depending on utilization for a MySQL Single-AZ instance. Depending on your utilization, the most savings are provided by the reserved instance type with the lowest effective hourly rate.
* Rates are compared for an Extra Large DB instance running in US East region, % savings on effective hourly rates are the same for all instance types
** Utilization = % of time your instance is running:
25% utilization of a 1 year term = 3 months
30% of utilization of a 3 year term = 11 months
Customers using both Reserved and On-Demand DB Instances will have Reserved Instance rates applied first to minimize costs. Each hour, if the number of running instances is less than or equal to the number of applicable Reserved Instances you have, all running DB instances will be charged at the Reserved Instance hourly rate. When your total quantity of running DB instances exceeds the number of applicable Reserved Instances you own, you will be charged the On-Demand rate.
For example, if you own 3 Reserved Instances with the same instance type in a given region, the billing system checks each hour to see how many total instances you have running that match those parameters. If it is 3 or less, you will be charged the Reserved Instance Rate for each instance running that hour. If more than 3 are running, you will be charged the On-Demand rate for the additional instances.
If you purchase a Reserved Instance in a given region where you have a running DB Instance, the lower hourly charge will automatically be applied to that instance moving forward with no need to restart.
How To Purchase Reserved Instances
Reserved Instances can be purchased using the AWS Management Console or API tools.