A company purchased a 1-year Standard Reserved Instance covering an m5.large in us-east-1 for a steady workload. Six months into the term, the workload permanently moves to a c6g.large, a different instance family built on a different processor architecture, for the remainder of the term. Which statement is correct?
- The Standard RI can simply be exchanged for a c6g.large RI covering the remaining term
- The Standard RI cannot change instance family; only a Convertible RI supports exchanging into a different instance family
- Both Standard and Convertible RIs can freely change instance family at any point during their term
- No Reserved Instance type ever supports a mid-term change; the company must wait until renewal
Correct answer: B. The Standard RI cannot change instance family; only a Convertible RI supports exchanging into a different instance family
Standard Reserved Instances allow limited modifications during their term, such as changing Availability Zone, scope, network platform, or instance size within the same instance family and generation, but they can never be exchanged into a different instance family, which rules out the m5-to-c6g move described here. Only Convertible Reserved Instances support mid-term exchange into a different configuration, including a different instance family, operating system, or tenancy, provided the new RI's value is equal to or greater than the value being exchanged, which is exactly why Convertible RIs carry a smaller discount than Standard RIs in exchange for that flexibility. The first option is wrong specifically because this purchase is a Standard RI, not a Convertible one. The third option overstates what Standard RIs can do, since their modification options never include changing family. The fourth option is wrong because Convertible RIs exist precisely to support this kind of mid-term family change before the original term ends.
Source: AWS documentation: Reserved Instances — modifying Standard RIs and exchanging Convertible RIs