Tair (Redis® OSS-Compatible):Enable automatic scale-up

Billing

Only the fees generated by upgrading the instance type will be charged. For more information, see Upgrade/Downgrade.

Automatic scale-up process

Figure 1. Automatic scale-up process

After you enable the automatic scale-up feature, when the average memory usage of the instance within the observation window reaches the specified threshold, DAS automatically performs the scale-up operation (upgrading the instance type to the next larger specification, for example, from 1 GB to 2 GB). After the scale-up is completed, DAS continues to monitor the memory usage. If the conditions for automatic scale-up are met again, DAS will continue to scale up until it reaches the maximum instance type you set.

However, DAS will not directly perform scale-down operations on the instance. If you enable the subscription service, when the average memory usage of the instance within the observation window drops below 30%, DAS will send you scale-down recommendations through your specified method (such as email). You can perform manual downgrade operations at an appropriate time to improve resource utilization. For specific operations about the subscription service, see the procedure section of this topic.

Impact of automatic scale-up

• When the instance is switched, there will be one or two transient connections within 30 seconds.

• To ensure that the new instance after configuration change can quickly catch up with the incremental data of the original instance, and to avoid data double-write caused by DNS cache, the instance will be in read-only state for about 1 minute during the configuration change.

• To provide better performance and stability, if the minor version of the instance is too low, the system will upgrade the minor version of the instance to the latest during the configuration change.

Procedure

1. Log on to the console and go to the Instances page. In the top navigation bar, select the region in which the instance is deployed. Then, find the instance and click its ID.

2. In the Configuration Information section, turn on the Automatic Scale-up switch.

3. In the DAS console dialog box that appears, complete the automatic scale-up and event subscription settings.

   1. On the Autonomous Function Settings > Optimization And Flow Control tab, select Automatic Scale-up and set the automatic scale-up parameters.

      Configuration	Description
      Average Memory Usage Is Not Less Than	Select the average memory usage threshold for automatic scale-up, in percentage. The value ranges from 50% to 90%, with an adjustment granularity of 10%.
      Specification Limits	Select the maximum instance type to which the instance can be scaled up. If the automatic scale-up threshold is reached, DAS will gradually scale up the instance type (for example, from 1 GB to 2 GB) and continue to monitor the memory usage. If the automatic scale-up threshold is reached again within the observation window, DAS will continue to scale up until it reaches the maximum instance type you set.
      Observation Window	Select the time for the observation window, in minutes. The maximum value is 30 minutes. Note The settings in this example indicate that if the average memory usage is greater than or equal to 70% within the 30-minute observation window, the system will upgrade the instance configuration (up to a maximum of 64 GB).

   2. Click OK.

      You will be returned to the Tair console page. The Automatic Scale-up status of the instance will be displayed as Enabled.

      If no alert template is configured for the instance, you can continue to configure alert subscription to stay informed about the automatic scale-up of the database instance.

   3. Select an alert template and click Template Selection Completed, Next.

      The system will recommend an alert template and add alert rules for the corresponding autonomous events. You can follow the system prompts to configure.

      Note

      • If you have already configured an alert template for the instance, follow the system prompts to add alert rules for the corresponding autonomous events to the alert template.

      • To set up alert templates and alert rules yourself, see Configure alert templates and Configure alert rules.

   4. Select an alert contact group and click Contact Group Selection Completed, Next.

      For operations to add contact groups or contacts, see Manage alert contacts.

   5. Click Submit Configuration and confirm the alert configuration in the dialog box that appears.

      You have now completed the alert subscription configuration.

FAQ

• Q: After enabling automatic scale-up for an instance, the Memory Usage is very high (such as 82%), why hasn't it automatically upgraded?

  A: Check the average memory usage threshold for automatic scale-up. For example, if it is set to 90%, it means that automatic scale-up will be performed when the average memory usage of the instance reaches 90% or above during the observation window.

• Q: Why is the automatic scale-up feature disabled after enabling read/write splitting?

  A: Because currently only standard architecture supports the automatic scale-up feature, the automatic scale-up feature will be disabled after read/write splitting is enabled.

References

Redis Open-Source Edition cloud-native cluster architecture instances also support automatic shard addition. For more information, see Automatic shard addition.