Reserved Instances for RDS Aurora

Question

A customer with 10 RDS (Aurora MySQL) instances (T2.small, R4.large).

If they buy T3 reserved instances (RI):

-  can they use these credits for any T type instance from any size? ex, to a T2.small (or later) if you initiate a new generation under the same T family (e.g. T4)

- could they use half of these RI for T3.large?

- is there a mapping table? ex. "T3.large equals 2+ T2.small".
 
- are RI interchangeable with different types? ex. buying a T3.small RI counts for a R4.large

Thanks

pechung · Accepted Answer

No, the customer will not have the flexibility to change instance generations. "Region, DB Engine, DB Instance Class, Deployment Type and term length must be chosen at purchase, and cannot be changed later" as indicated on [this][1] page.

If a customer would like to purchased T3 reserved instances for RDS, they will have to commit to the T3 family. With Aurora MySQL they have [size flexibility][2] -- so they can purchase a T3.Large, and run 4 T3.Smalls to get the discount (or whatever the size factor is). However, they must commit to the T3 family. They will not be able to get the discount by running a T2 RDS instance. That T2 will be billed on-demand rates.

[1]: https://aws.amazon.com/rds/reserved-instances/
  [2]: https://aws.amazon.com/about-aws/whats-new/2017/10/amazon-rds-reserved-instances-offer-instance-size-flexibility/

Reserved Instances for RDS Aurora

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