AWS Reserved Instances - Windows Server Criteria

Question

We have a two R3.4xlarge instances running MS-SQL on a windows server.

One is reserved and other is on demand. We currently start-stop between those instances (only one of them is running at a time), to avail RI benefits.

Can we launch both these instances at the same time as a scale-down R3.2xlarge instances and get the RI savings from one R3.4xlarge? Are there any RI limitations for Windows platform?

thanks -Ravi

Answer 1

While that feature does exist for Linux/Unix instances, this does not apply to Windows Instances.

Instance size flexibility does not apply to Reserved Instances that are purchased for a specific Availability Zone, bare metal instances, Reserved Instances with dedicated tenancy, and Reserved Instances for Windows, Windows with SQL Standard, Windows with SQL Server Enterprise, Windows with SQL Server Web, RHEL, and SLES.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/apply_ri.html