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Article Amazon Web Services March 14, 2017

AWS EC2 Regional RI: Enhanced and Even Easier to Use

Amazon Web Services announced yesterday that they had altered the application structure of Regional EC2 Reserved Instances to make them even easier for customers use. As the announcement stated:

Effective March, 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.

This is being applied to all currently owned RIs and all future purchases. Users no longer need to match the size constraint for shared tenancy Regional RIs. AWS will automatically apply your Regional RI to any available instance within the family. Jeff Barr, AWS Chief Evangelist, provides a detailed description of EC2 RI application here.

Late last year, AWS launched Regional RIs. This RI type allows application to an instance tied to a specific AWS Region, rather than an AZ. The removal of the AZ designation allows the user to launch an instance without having to worry about launching in the AZ that is eligible for the RI discount. When you have highly scalable workloads, this is a significant advantage.

There is an important limitation: In return for the flexibility of AZ application, the RI owner forfeits guaranteed availability.

We would recommend using a mixture of Regional and Standard RIs, to ensure minimum available capacity.

Imagine owning a Regional RI for a m4.4xlarge. This RI now applies to any usage of a Linux/UNIX M4 instance with shared tenancy in the region. The new enhancement will enable the automatic application of that RI as follows:

  • One m4.4xlarge instance
  • Two m4.2xlarge instances
  • Four m4.xlarge instances

The enhancement also includes other combinations such as one m4.2xlarge and four m4.large instances.

AWS will even pro-rate the discount for partial RI if the user has instances than cannot be fully applied. For example, imagine owning an RI for an m4.xlarge, but scale up to a m4.2xlarge instance. Now, users will only pay half of the On-Demand, per-hour price for the larger instance.

The bottom line: AWS just added another compelling reason to buy RIs.

Here at CloudCheckr, we are working to support this new enhancement so that our users continue to receive the benefits of the most robust RI management platform on the market. If you are not already using CloudCheckr, we invite you to contact sales for short demo or start your own free trial today. With AWS updates that constantly make RI usage more effective, it’s easy to start using them immediately to recognize savings.

Try CloudCheckr free for 14 days to start optimizing your use of Reserved Instances. 

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