Burstable instances (t5 and t6 instances) support the unlimited and standard modes to meet the requirements of different business scenarios. This topic describes how to view the performance mode of a burstable instance and enable or disable the unlimited mode for the instance.
Background information
Standard mode: The performance of a burstable instance in standard mode is limited by the availability of CPU credits. After the initial credits and CPU credit balance of the instance are depleted, the instance is unable to burst beyond its performance baseline.
Unlimited mode: The performance of a burstable instance in unlimited mode is not subject to the availability of CPU credits. You can overdraw or purchase additional CPU credits. The instance can spend the additional CPU credits to burst beyond its performance baseline.
In unlimited mode, you may be charged for the additional CPU credits that burstable instances spend to burst performance. For more information, see Additional fees.
In the following scenarios, the system selects or switches the performance mode for a burstable instance:
When you create burstable instances, the standard mode is used for the instances by default.
If a burstable instance is in the Stopped state and economical mode, the instance runs in standard mode after the instance is restarted.
If a burstable instance is in the Stopped state and is not in economical mode, the performance mode used before the instance is stopped still takes effect after the instance is restarted.
If you have overdue payments in your account, the unlimited mode is automatically disabled for burstable instances and is not re-enabled until you complete the payments.
View the performance mode of a burstable instance
Log on to the ECS console.
In the left-side navigation pane, choose .
In the top navigation bar, select the region and resource group to which the resource belongs.
(Optional) If the Unlimited Mode column is not displayed on the Instance page, perform the following operations to show the column:
Click the
icon in the upper-right corner. In the Instance List Settings dialog box, find the Unlimited Mode option in the Columns Not Displayed section, click the
icon to the right, and then click Continue.
In the Unlimited Mode column, view the performance mode of the burstable instance.
Disabled: indicates that the instance runs in standard mode.
Enabled: indicates that the instance run in unlimited mode.
Enable the unlimited mode
You can enable the unlimited mode for burstable instances based on your business requirements to allow the instances to burst beyond the baseline CPU utilization.
Make sure that the burstable instance is in the Running state. Otherwise, you cannot switch the performance mode for the instance.
Log on to the ECS console.
In the left-side navigation pane, choose .
Find a burstable instance that runs in standard mode and use one of the following methods to enable the unlimited mode for the instance:
To enable the unlimited mode for a single burstable instance, choose
> Instance Attributes > Enable Unlimited Mode in the Actions column. 
To enable the unlimited mode for one or more burstable instances at a time, select the instances and choose in the lower-left corner of the Instance page.
In the Enable Unlimited Mode dialog box, select I am aware of the costs and risks. and click Confirm.
Disable the unlimited mode
You can disable the unlimited mode for burstable instances to limit the CPU utilization of the instances to the baseline level.
Make sure that the burstable instance is in the Running state. Otherwise, you cannot switch the performance mode for the instance.
Log on to the ECS console.
In the left-side navigation pane, choose .
Find a burstable instance that runs in unlimited mode and use one of the following methods to disable the unlimited mode for the instance:
To disable the unlimited mode for a single instance, choose
> Instance Attributes > Disable Unlimited Mode in the Actions column. 
To disable the unlimited mode for one or more burstable instances at a time, select the instances and choose in the lower-left corner of the Instance page.
In the Disable Unlimited Mode message, click Confirm.
FAQ
How do I view the changes in CPU credits of a burstable instance?
You can go to the details page of a t5 or t6 burstable instance and click the Monitoring tab to view the changes in CPU credits of the instance in the Consumed CPU Credits, Accrued CPU Credits, Surplus CPU Credit (which shows overdrawn CPU credits), and Advance CPU Credits charts.
After you enable the unlimited mode for a burstable instance, you may be charged additional fees for the instance in the following scenarios:
The burstable instance uses up advance CPU credits and starts to spend overdrawn CPU credits. You are billed and charged for the overdrawn CPU credits by the hour.
The burstable instance spent advance CPU credits. Before the advance CPU credits are replenished, the burstable instance is stopped in economical mode, is released, has its configurations changed, or switches to the standard mode. You are charged a lump sum for the advance CPU credits.
For more information, see Billing.
How do I view the time at which the unlimited mode was enabled?
You can go to the Operation Logs page in the ECS console, select Operation Name from the drop-down list, and then set Operation Name to ModifyInstanceAttribute. Find a ModifyInstanceAttribute operation, click the plus (+) sign to the left, and then click View Details. In the Operation Details message, if the value of the CreditSpecification parameter is Unlimited, the instance is in unlimited mode. In this case, the time displayed in the Operation Time column is the time at which the unlimited mode was enabled.
