The RDS Flexible (Special Offer) savings plan is a discount program for RDS Serverless instances that helps you offset your bills for RCU and storage. This plan is ideal if your RDS Serverless instances have fluctuating workloads or unpredictable usage times. Unlike a general-purpose savings plan, it does not require an hourly commitment. Instead, your usage is billed at a discounted rate, and the system deducts the cost from the plan's total offset amount. This offers greater flexibility than a general-purpose savings plan.
Overview
The Flexible (Special Offer) savings plan is a discount program that applies to the RCU and storage billable items for RDS Serverless instances.
You only prepay a committed spend. The system then calculates a total offset amount based on your committed spend. This amount covers the RCU and storage bills for your Serverless instances over a six-month period. If the total offset amount is not fully used by the end of the six-month period, the remaining offset amount expires. If the offset amount is depleted before the six-month period ends, subsequent RCU and storage costs for your Serverless instances are charged directly to your account.
Purchase
Use cases
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Scenario 1: You have RDS Serverless instances with fluctuating workloads, which causes their hourly RCU and storage costs to vary.
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Scenario 2: You use services intermittently. For example, you purchase an RDS Serverless instance for learning or testing and use it for only a few hours each day.
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Scenario 3: You use both RDS Serverless instances and fixed-specification instances (subscription or pay-as-you-go). If the workloads of your Serverless instances often fluctuate, you can use a general-purpose savings plan to offset some of the pay-as-you-go costs for your fixed-specification instances, and use a Flexible (Special Offer) savings plan to offset the Serverless RCU and storage costs.
Offset rules
Eligible billable items
RCU and storage costs for RDS Serverless instances.
Offset amount
The committed spend does not directly offset your RDS pay-as-you-go bills. The offset amount, which is calculated based on the committed spend and a discount rate, is used to offset your RDS pay-as-you-go bills. The formula is:
Stacking rules and offset order
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You can purchase multiple Flexible (Special Offer) savings plans. During cost offset, the system applies plans in order of their expiration date, with the earliest expiring plan applied first. If multiple plans have the same expiration date, the one purchased earliest is applied first.
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You can have both general-purpose and Flexible (Special Offer) savings plans at the same time. During cost offset, the system applies general-purpose savings plans first.
Offset examples
Assume you purchase a Flexible (Special Offer) savings plan with a committed spend of CNY 500. This provides a total offset amount of CNY 1,250 (500 / 0.4).
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Scenario A: You have a Serverless Basic Edition instance that consistently uses 0.5 RCU and 20 GB of storage per hour. The hourly cost for RCU and storage is CNY 0.2005 (CNY 0.333/RCU/hour * 0.5 RCU + CNY 0.0017/GB/hour * 20 GB), which is deducted from your offset amount. At the end of the six-month period, a total of CNY 866.16 (CNY 0.2005/hour * 24 hours * 180 days) of the offset amount has been consumed. The remaining CNY 383.84 expires.
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Scenario B: You have one Serverless High-availability Edition instance and one Serverless Basic Edition instance. The High-availability Edition instance consistently uses 2 RCUs and 100 GB of storage per hour. The hourly cost for RCU and storage is CNY 0.836 (CNY 0.333/RCU/hour * 2 RCUs + CNY 0.0017/GB/hour * 100 GB), for a daily cost of CNY 20.064. The Basic Edition instance runs for 14 hours a day, using 2 RCUs and 100 GB of storage at an hourly cost of CNY 0.836. It is paused for 10 hours a day, during which RCU billing stops, but the 100 GB of storage continues to be billed at an hourly cost of CNY 0.17. The total daily cost for the Basic Edition instance is CNY 13.404. In this scenario, the offset amount from your Flexible (Special Offer) savings plan is expected to be depleted by the 38th day (CNY 1,250 / (CNY 20.064 + CNY 13.404)).
Estimate your committed spend
On the Cost Analysis page, you can review the total cost of RCU and storage for your RDS Serverless instances over the past six months. Use this total as a reference to estimate your committed spend.
Set Cost Type to List Price and Group By to Product to view the total cost.
Because you cannot change the committed spend or cancel a savings plan after purchase, we recommend starting with a lower committed spend. You can purchase a new savings plan when your current one is nearly depleted.