Assured serverless

Feature overview

Assured serverless automatically adjusts the CPU and memory of your fixed-specification ApsaraDB RDS for PostgreSQL instance based on its workload. This helps your instance handle unpredictable traffic spikes, reduce costs, and improve resource utilization.

• For workloads with unpredictable traffic spikes, the feature automatically scales up your instance when a spike occurs. This enhances instance stability and ensures business continuity.

• After a traffic spike ends, the feature automatically scales down your instance based on its CPU and memory usage to prevent resource waste and control operational costs.

Prerequisites

Your ApsaraDB RDS for PostgreSQL instance must meet the following conditions:

• Product type: Standard

• Billing method: subscription, pay-as-you-go

• Supported regions and zones

  Region	Zone
  China (Hangzhou)	Zone I, Zone J, Zone K
  China (Shanghai)	Zone B, Zone E, Zone G, Zone L, Zone M, Zone N
  China (Shenzhen)	Zone C, Zone E, Zone F
  China (Heyuan)	Zone A, Zone B
  China (Guangzhou)	Zone A, Zone B
  China (Beijing)	Zone F, Zone G, Zone I, Zone J, Zone K, Zone L
  China (Zhangjiakou)	Zone B, Zone C
  China (Ulanqab)	Zone B, Zone C
  China (Chengdu)	Zone A, Zone B
  China (Hong Kong)	Zone B, Zone C, Zone D
  South Korea (Seoul)	Zone A
  Singapore	Zone A, Zone B, Zone C
  Malaysia (Kuala Lumpur)	Zone A, Zone B
  Indonesia (Jakarta)	Zone A, Zone B, Zone C
  Thailand (Bangkok)	Zone A
  Germany (Frankfurt)	Zone A
  UK (London)	Zone A, Zone B

Billing

During the public preview, when an instance is scaled up using assured serverless, the additional resources are provided free of charge and you are billed only for the original instance specifications.

Usage notes

• This feature is in public preview. During the public preview, instances with assured serverless enabled are not covered by the Service Level Agreement (SLA). However, the service level of your instance is not downgraded.

• While your instance is temporarily scaled up using assured serverless, you cannot perform operations such as change configurations, migrate zones, or upgrade major or minor versions.

Enable assured serverless

1. 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.

2. On the Basic Information page, find the Configuration Information section and click Settings next to Assured Serverless.

3. In the Assured Serverless Settings dialog box, turn on the feature switch and configure the parameters.

   Parameter	Description
   Resources Threshold for Assured Serverless	Configure the Maximum CPU Resources and Maximum Memory for auto-scaling. Maximum CPU Resources: Scales in 1-core increments, up to twice the initial CPU configuration of the instance. Maximum Memory: Measured in GB. Scales in 2 GB increments, up to twice the initial memory configuration of the instance.
   Effective Policy	Select when the settings will take effect. Immediate Within Maintenance Window. The settings take effect during the configured Maintenance Window of the instance. You can view and configure the Maintenance Window in the Configuration Information section. Note If the current host has insufficient resources when the settings take effect, your instance may be migrated to another host. This migration causes a transient interruption lasting several minutes. We recommend setting this change to take effect during off-peak hours.
   Upgrade Threshold	The CPU Threshold and Memory Threshold that trigger a scale-up event. When the CPU utilization or memory usage of the instance exceeds the specified thresholds, the system automatically scales up the CPU and memory to the configured upper limits. Note When the CPU or memory usage exceeds the upgrade threshold, assured serverless scales directly to the configured upper limit. In contrast, a serverless instance scales gradually based on workload fluctuations.
   Downgrade Threshold	The CPU Threshold and Memory Threshold that trigger a scale-down event. During a 90-second observation window, if both the CPU and memory usage of the instance remain below the specified thresholds, the system automatically scales down the CPU and memory in steps (1 core for CPU, 2 GB for memory) toward the instance's initial specifications. If the CPU or memory usage exceeds the configured Upgrade Threshold during the observation window, the system maintains the current specifications or scales up to the configured upper limit. The system resumes the scale-down process only after both the CPU and memory usage fall below the Downgrade Threshold again.

4. Click OK.