You can use the scheduled automatic scaling feature of Database Autonomy Service (DAS) to manage database loads that change cyclically. This feature is useful for predictable traffic spikes, such as those that occur during promotions. You can schedule a time to scale out your instance type to handle the increased load. After the scheduled period ends, the system restores the instance to its original type. This process helps you meet your business needs while controlling costs.
Prerequisites
The instance versions are as follows:
RDS MySQL 8.0 High-availability Edition with cloud disks (General-purpose)
RDS MySQL 5.7 High-availability Edition with cloud disks (General-purpose)
Ensure that your account has a sufficient balance to cover the scale-out costs.
A service-linked role for DAS has been created.
Precautions
To scale up a database instance on a regular basis, you must configure a scheduled auto scaling policy for the database instance.
All time-related parameters are displayed in UTC+8. If this time zone is not supported in your region, you must convert the time before you configure the parameters.
You can apply only one auto scaling policy of each mode to a database instance.
Retry intervals are not supported for scheduled auto scaling policies. If a scheduled auto scaling policy fails to be executed, the system does not retry to execute the policy.
If the Duration or Scale-back Time parameter is modified after an instance is scaled up, the instance is scaled back to the previous specifications based on the new time specified by either of the two parameters.
In the following scenarios, the database instance may not be scaled back to its previous specifications even if the Duration or Scale-back Time parameter is specified:
The specifications of the database instance are manually or automatically changed again after the scheduled auto scaling policy is executed. If the instance specifications are different from those specified in the policy, the database instance is not scaled back.
One or more metrics of the database instance do not meet specific standards. For example, the memory of an instance is scaled up from 1 GB to 4 GB based on a scheduled auto scaling policy. If 1 GB of memory has been used before the instance is scaled back, the scale-back operation is not performed because the memory usage increases to 100% during the operation. This ensures the stability and security of your business.
The instance is in a state in which specification changes are not allowed, such as the Changing Specifications or Migrating state.
Examples
DAS performs scaling operations on your instances once or on a regular basis. DAS may scale your instances every day, week, or month. For example, if the peak hours of your business start at 2:00 on the first day of every month and end at 2:00 on the third day of every month, you can use the scheduled auto scaling feature to scale up your instances during peak hours and scale the instances back during off-peak hours.
Billing
When you use scheduled automatic scaling to change the instance type of a database instance, you are charged for the change. For more information, see Change specifications.
Add a scheduled automatic scaling policy
Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the navigation pane on the left, select . On the Autonomy Center page, click Autonomy Service Settings.
On the tab, click Add Policy. On the Add Policy page, set the following parameters:
Parameter
Description
Policy Name
The name of the policy.
Mode
For the policy pattern, select Scheduled Auto Scaling.
Engine Type
The type of the database engine.
Specifications
The instance type of the selected database engine.
Operation
Currently, only Adjust Instance Specifications is supported.
Valid From
Valid From includes Start Date and End Date.
Start Date is required. The value must be later than or equal to the current date.
End Date is optional.
When Recurrence is set to Not Set (executes Only Once), the end time of the scheduled auto scaling policy is not constrained by the End Date.
When Recurrence is set to Daily, Weekly, or Monthly, the scheduled auto scaling policy runs periodically and indefinitely if you do not set an End Date. If you set an End Date, the end time of the policy is constrained by the specified End Date.
Recurrence
Valid values:
Not Set (One-time Execution)
Scaling Start Time: Required parameter.
Duration: An optional parameter. The value is a positive integer in hours.
If you do not set the Duration, the instance specifications are not restored to their original state after the scheduled auto scaling policy is executed.
Setting Duration means that after the specified duration ends, the scheduled auto scaling policy restores the instance type to the type that was used before the policy was executed.
Daily
Scaling Start Time: Required parameter.
Scale-back Time: Required parameter.
If the Scaling Start Time is earlier than the Scale-back Time, this means that the scheduled auto scaling policy starts and ends on the same day within a single cycle.
If the Scaling Start Time is later than the Scale-back Time, it indicates that the scheduled auto scaling policy does not start and end on the same day within a single cycle. The Scaling Start Time is on the current day, and the Scale-back Time is on the next day.
NoteThe time interval between Scaling Start Time and Scale-back Time must be at least 1 hour.
The interval between the Scaling Start Time and the Scale-back Time of the scheduled auto scaling policy for the previous cycle must be at least 1 hour.
If an End Date is set and it falls between the Scaling Start Time and Scale-back Time of a cycle, the scheduled auto scaling policy for that cycle will not be executed.
Weekly
Scaling Start Time: Required parameter.
Scale-back Time: Required parameter.
If Scaling Start Time < Scale-back Time, this indicates that within a single cycle, the scheduled auto scaling policy starts and ends in the same week.
If Scaling Start Time > Scale-back Time, this indicates that the start and end of the scheduled auto scaling policy cycle do not occur in the same week. The Scaling Start Time is a point in time in the current week, and the Scale-back Time is a point in time in the next week.
NoteThe time interval between Scaling Start Time and Scale-back Time must be at least 1 hour.
The Scaling Start Time must be at least 1 hour after the Scale-back Time of the scheduled auto scaling policy for the previous cycle.
If the End Date is between the Scaling Start Time and the Scale-back Time of an epoch, the scheduled auto scaling policy for that epoch will not be executed.
Monthly
Scaling Start Time: Required parameter.
Scale-back Time: Required parameter.
If Scaling Start Time < Scale-back Time, this means that the scheduled auto scaling policy starts and ends in the same month within a single cycle.
If the Scaling Start Time is later than the Scale-back Time, this means that the start and end times for the scheduled auto scaling policy cycle fall in different months. The Scaling Start Time is in the current month, and the Scale-back Time is in the next month.
NoteThe time interval between Scaling Start Time and Scale-back Time must be at least 1 hour.
The time interval between the Scaling Start Time and the Scale-back Time of the scheduled auto scaling policy from the previous cycle must be at least 1 hour.
If the End Date falls between the Scaling Start Time and the Scale-back Time of an epoch, the scheduled auto scaling policy for that epoch will not be executed.
On the Add Policy page, click OK.
In the Recommended Policies section, find the desired policy and click Apply in the Actions column to add the policy to the instance.
NoteTo modify the policy, click Modify in the Actions column and make changes on the Update Policy tab.
To cancel the policy for the instance, click Cancel Policy in the Actions column of the Applied Policies section.
On the Autonomous Function Management page, click OK.
(Optional) Configure the Alert Template to subscribe to alerts and stay informed about the scheduled automatic scaling of the database instance.
The system recommends an alert template and adds alert rules for the corresponding autonomy events. You can follow the prompts to complete the configuration.
NoteIf you have already configured an alert template for the instance, follow the prompts to add alert rules for the corresponding autonomy events to the template.
To configure the alert template and alert rules yourself, see Configure an alert template and Configure alert rules.
Select the Alert Contact Group to receive alert notifications.
Click Add Contact to add a new alert contact.
Click Add Contact Group to add a new alert contact group.
In the row of the target contact, click Modify or Remove to modify or delete the contact's information.
For more information, see Manage alert contacts.
Confirm the Linked Instance.
Click Submit Configuration, and confirm the alert configuration in the dialog box that appears.
View the results of scheduled automatic scaling
Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the navigation pane on the left, select .
On the Autonomy Center page, view the Auto-Scaling Events that occurred within the selected time range.
Click Details in the row of an Auto-Scaling Events to view detailed information about the scheduled automatic scaling.
FAQ
Q: What do I do if my instance cannot be scaled out because it has reached the maximum specifications of its instance family?
A: You can purchase an instance with higher specifications from a different instance family. For example, the high-availability Dedicated instance type for RDS MySQL supports up to 104 cores and 768 GB of memory. Then, you can migrate data from your current instance to the new one. For more information about instance types and data migration, see RDS for MySQL instance types and Migrate data between RDS instances.
References
To change your instance type as your business grows, see Change specifications. You can also enable automatic performance extension. If you enable this feature, the system automatically scales out the instance based on workload changes.