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- All up front
- Biggest discount
- Full payment is made at the start of the term, with no other costs incurred for the remainder of the term, regardless of hours used.
- Partial up front
- A portion of the cost must be paid upfront and the remaining hours in the term are billed at a discounted hourly rate, regardless of usage.
- No up front
- One year term
- Available with a 3 year term for C4, M4, R4, I3, P2, X1, and T2 Standard Reserved Instances only
- You are billed a discounted hourly rate for every hour within the term, regardless of usage, and no upfront payment is required.
Billing
- NOTE with the recent announcement of per-second billing for EC2 instances you can launch, use, and terminate multiple instances within an hour and get the Reserved Instance Benefit for all of the instances.
- Reserved Instances are billed for every clock-hour during the term that you select, regardless of whether an instance is running or not.
Reserved Instance billing benefits only apply to one instance-hour per clock-hour.(This needs to be confirmed for current applicability.)- A new instance-hour begins after an instance has run for 60 continuous minutes, or if an instance is stopped and then started. Rebooting an instance does not reset the running instance-hour.
For example, if an instance is stopped and then started again during a clock-hour and continues running for two more clock-hours, the first instance-hour (before the restart) is charged at the discounted Reserved Instance rate. The next instance-hour (after restart) is charged at the On-Demand rate and the next two instance-hours are charged at the discounted Reserved Instance rate.(This needs to be confirmed for current applicability.)
Consolidated Billing
- You cannot control which instances are billed at the discounted rate
- If you leverage Consolidated Billing, AWS will use the aggregate total list price of active RIs across all of your consolidated accounts to determine which volume discount tier to apply.
- Additional savings begin at $500k
- Convertible RIs do not receive volume discounts however the value of each Convertible RI that you purchase contributes to your volume discount tier standing.
- Reserved Instances are first applied to usage within the purchasing account, followed by qualifying usage in any other account in the organization. The Reserved Instance discount is applied to qualifying usage that is detected first by the AWS billing system.
- In general, Reserved Instances that are owned by an account are applied first to usage in that account. However, if there are qualifying, unused zonal Reserved Instances in other accounts in the organization, they are applied to the account before regional Reserved Instances owned by the account.
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