...
- All Regional Linux/UNIX RIs with shared tenancy now apply to all sizes of instances within an instance family and AWS region, even if you are using them across multiple accounts via Consolidated Billing.
- RIs with Instance Size Flexibility use a concept of normalized units to apply billing credits.
Let’s say you already own an RI for a c4.8xlarge (normalization factor of 64). This RI now applies to any usage of a Linux/UNIX C4 instance with shared tenancy in the region. This could be:
- One c4.8xlarge instance.
- Two c4.4xlarge instances (normalization factor of 32 each) instances (64 total).
- Four c4.2xlarge instances2xlarge (normalization factor of 16 each) instances (64 total).
- Sixteen c4.large instanceslarge (normalization factor of 4 each) instances (64 total).
- It also includes other combinations such as one c4.4xlarge and eight c4.large instances.
- If you own an RI that is has a smaller normalization factor than the instance that you are running, you will be charged the pro-rated, On-Demand price for the excess.
If you own an RI for a large instance and run a smaller instance, the RI price will apply to the smaller instance. However, the unused portion of the reservation will not accumulate.
Note Instance size flexibility does not apply to Windows, Windows with SQL Standard, Windows with SQL Server Enterprise, Windows with SQL Server Web, RHEL, and SLES Reserved Instances.
Guaranteed Capacity
- If an Availability Zone is specified, EC2 reserves capacity matching the attributes of the RI. The capacity reservation of an RI is automatically utilized by running instances matching these attributes.
...