The actual performance of burstable instances is determined based on CPU credits. This helps you control costs when you purchase computing capabilities. If your burstable instances consume additional CPU credits, you are charged additional fees. Therefore, the fees for a burstable instance contains the instance purchase fee and additional fees.
Instance purchase fee
Same as other instance families, burstable instances support pay-as-you-go and subscription billing methods. For more information about the difference between pay-as-you-go and subscription, see Comparison of billing methods. For information about the prices of burstable instances, see Pricing overview.
Burstable instances can be preemptible instances. For more information, see Overview.
- You can purchase only zonal reserved instances.
- You cannot split or merge reserved instances.
Impact of performance modes on billing
When you purchase or use a burstable instance, you can choose whether to enable the unlimited mode for the burstable instance. The billing of a burstable instance is related to its performance mode. The following table describes the differences between the billing of burstable instances in different performance modes.
| Performance mode | Instance purchase fee | Additional fee |
|---|---|---|
| Standard mode | The purchase fee is determined by the billing method, not by the performance mode of the instances. For more information, see Instance purchase fee. | You are not charged additional fees when you use burstable instances. |
| Unlimited mode | The purchase fee is determined by the billing method, not by the performance mode of the instances. For more information, see Instance purchase fee. |
You are charged additional fees in the following cases:
|
The following table describes how additional fees are charged in the unlimited mode.
| Region | Windows instance (USD/Credit) | Linux instance (USD/Credit) |
|---|---|---|
| Mainland China | 0.0008 | 0.0008 |
| Outside mainland China | 0.0016 | 0.0008 |
Cost comparison between burstable instances and enterprise-level instances
An ecs.t5-lc1m2.large burstable instance and an ecs.c5.large enterprise-level instance are used in this example. Both instances have two vCPUs and 4 GiB memory. Assume that the ecs.t5-lc1m2.large burstable instance has consumed all of the initial CPU credits, CPU credit balance, and advance CPU credits. The following figure shows the cost trends for two instances when overdrawn CPU credits are used.
In the preceding figure, the hourly pay-as-you-go price is calculated based on the configurations of the ecs.t5-lc1m2.large burstable instance (such as baseline CPU performance of 10% and two vCPUs) and the prices of the overdrawn CPU credits (such as for a Linux instance in the China (Beijing) region). For other instance types, the calculation method is the same, but the specific CPU utilization threshold is different.
- If the average CPU utilization is less than 57.83%, the cost of the ecs.t5-lc1m2.large burstable instance is lower than that of the ecs.c5.large enterprise-level instance.
- If the average CPU utilization is equal to 57.83%, the cost of the ecs.t5-lc1m2.large burstable instance is equal to that of the ecs.c5.large enterprise-level instance.
- If the average CPU utilization is greater than 57.83%, the cost of the ecs.t5-lc1m2.large burstable instance is higher than that of the ecs.c5.large enterprise-level instance.
Therefore, you can choose instance types based on the expected CPU utilization threshold to ensure service availability and control your costs.
The following figures show the cost trends of several popular burstable instance types. To learn more about other burstable instance types, submit a ticket.
