Tair (Redis® OSS-Compatible):Scheduled auto scaling

Prerequisites

• The instance is a Redis Open-Source Edition or a memory-optimized Tair (Enterprise Edition) instance.

• The instance uses the standard architecture.

• The instance is a cloud-native edition.

• A DAS service-linked role has been created.

• Your account must have a sufficient balance for the scale-out.

Notes

• Currently, scheduled auto scaling supports only the scale-out of database instances using preset policies.

• All time settings are based on the UTC+8 time zone. If your database instance is in a different time zone, you must convert the times manually.

• You can apply only one scaling policy of the same pattern to an instance.

• Scheduled auto scaling does not support automatic retries. If a scaling rule fails to execute, it is not retried.

• If you modify the Duration or Scale-back Time after a scale-out, the instance is restored to its original instance type based on the latest configuration.

• If you set a Duration or Scale-back Time, the instance may not be restored to its original instance type for the following reasons:

  • If another instance type change occurs during this period, such as a manual change or a dynamic scaling event, the instance is not restored. This occurs because the current instance type does not match the target instance type that is set in the scheduled auto scaling policy.

  • To ensure business stability and security, the instance is restored only if its metrics meet the downgrade conditions. For example, assume the original instance has 1 GB of memory and the target instance type has 4 GB of memory. Before the restoration, DAS checks the current memory usage. If the memory usage is 1 GB, restoring the instance to the original 1 GB instance type would result in 100% memory usage. The instance is not restored because this does not meet the restoration conditions.

  • If the instance is in a state where its configuration cannot be changed, such as during an instance type change or a migration, the restoration operation cannot be executed.

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 auto scaling to change the instance type of a database instance, you are charged for the upgrade or downgrade. For more information, see Upgrade/Downgrade.

Add a scheduled auto scaling policy

1. Log on to the console and go to the Instances page. In the top navigation bar, select the region in which the instance that you want to manage resides. Then, find the instance and click the instance ID.

2. In the navigation pane on the left, click CloudDBA > Performance Trends.

3. On the Performance Trends page, click Autonomy Service Settings.

4. On the Autonomous Function Settings > Auto Scaling tab, click Add Policy. On the Add Policy page, set the following parameters:

   Parameter	Description
   Policy Name	The name of the policy.
   Mode	The pattern of the policy. Select Scheduled Auto Scaling.
   Engine Type	The type of the database engine.
   Specifications	The instance type for the selected database engine.
   Operation	Select Adjust Instance Specifications to scale to the target size. Note 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 on or after the current date. End Date is optional. If Recurrence is set to None (run only once), the end time of the policy is not constrained by the End Date. If Recurrence is set to Daily, Weekly, or Monthly, the policy runs periodically and indefinitely if you do not set an End Date. If you set an End Date, the policy is constrained by the specified end date.
   Recurrence	Valid values: None (run only once) Scaling Start Time: Required. Duration: Optional. The value must be a positive integer in hours. If you do not set a Duration, the instance is not restored to its original instance type after the policy is executed. If you set a Duration, the instance is restored to its original instance type after the specified duration ends. Daily: Scaling Start Time: Required. Scale-back Time: Required. If Scaling Start Time<Scale-back Time, the scaling starts and ends on the same day within a cycle. If Scaling Start Time>Scale-back Time, the scaling starts and ends on different days within a cycle. The Scaling Start Time is on the current day, and the Scale-back Time is on the next day. Note The interval between the Scaling Start Time and the Scale-back Time must be at least 1 hour. The interval between the Scaling Start Time of the current cycle and the Scale-back Time of the previous cycle must be at least 1 hour. If you set an End Date that falls between the Scaling Start Time and the Scale-back Time of a cycle, the policy for that cycle will not be executed. Weekly Scaling Start Time: Required. Scale-back Time: Required. If Scaling Start Time<Scale-back Time, the scaling starts and ends in the same week within a cycle. If Scaling Start Time>Scale-back Time, the scaling starts and ends in different weeks within a cycle. The Scaling Start Time is in the current week, and the Scale-back Time is in the next week. Note The interval between the Scaling Start Time and the Scale-back Time must be at least 1 hour. The interval between the Scaling Start Time of the current cycle and the Scale-back Time of the previous cycle must be at least 1 hour. If you set an End Date that falls between the Scaling Start Time and the Scale-back Time of a cycle, the policy for that cycle will not be executed. Monthly Start Time (monthly): Required. Restore Time (monthly): Required. If Scaling Start Time<Scale-back Time, the scaling starts and ends in the same month within a cycle. If Scaling Start Time>Scale-back Time, the scaling starts and ends in different months within a cycle. The Scaling Start Time is in the current month, and the Scale-back Time is in the next month. Note The interval between the Scaling Start Time and the Scale-back Time must be at least 1 hour. The interval between the Scaling Start Time of the current cycle and the Scale-back Time of the previous cycle must be at least 1 hour. If you set an End Date that falls between the Scaling Start Time and the Scale-back Time of a cycle, the policy for that cycle will not be executed.

5. In the Recommended Policies section, find the policy that you want to add and click Apply in the Actions column to add the policy to the instance.

   Note

   • To modify a created policy, click Modify in the Actions column of the policy. Make changes on the Update Policy tab.

   • To remove an applied policy from an instance, go to the Applied Policies section and click Cancel in the Actions column.

6. Click OK.

View the results of scheduled auto scaling

1. Log on to the DAS console.

2. In the navigation pane on the left, click Instance Monitoring.

3. Find the target instance and click its instance ID to go to the instance details page.

4. In the navigation pane on the left, click Autonomy Center.

5. On the Autonomy Center page, view the Auto-Scaling Events that occurred within the selected time range.

6. Click Details for an Auto-Scaling Events to view detailed information about the event.

   

FAQ

Q: What should I do if my instance cannot be scaled out because it has reached the maximum instance type of its class?

A: You can purchase a new instance of a larger instance type from a different instance class. Then, you can migrate your data to the new instance. For more information about instance types and migration solutions, see Instance types and Instance migration.