ApsaraDB RDS:Assured serverless

Function introduction

The assured serverless feature elastically adjusts CPU and memory on fixed-specification RDS PostgreSQL instances based on workload to handle periodic traffic spikes, reduce usage costs, and improve resource utilization.

• For business scenarios with irregular traffic spikes, the instance automatically upgrades when traffic spikes occur, enhancing instance stability and ensuring business continuity.

• After traffic spikes end, the instance automatically downgrades based on CPU and memory usage to avoid resource waste and control database O&M costs.

Prerequisites

The RDS 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 period, when scaling up instance specifications through the assured serverless feature, no additional fees are charged for the added resources, and you are billed only for the original specifications.

Notes

• During the public preview, the instance performance will not be downgraded. However, instances with the assured serverless feature enabled do not guarantee the Service Level Agreement (SLA).

• When the assured serverless feature takes effect, if the current host resources are tight, instance migration (to an idle host) may occur, causing a transient connection of no more than 30 seconds. Therefore, we recommend that you configure the effective time during off-peak business hours.

• During the temporary automatic upgrade period of assured serverless, RDS for PostgreSQL instances do not allow operations such as changing configurations, migrating zones, or upgrading 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. In the Configuration Information section of the Basic Information page, click Settings next to Assured Serverless.

3. In the Assured Serverless Settings page that appears, turn on the feature switch and configure the related function parameters.

   Parameter	Description
   Resources Threshold for Assured Serverless	Configure the elastic scaling CPU Upper Limit and Memory Upper Limit. Maximum CPU Resources: Each adjustment is 1 core, with a maximum of twice the initial CPU configuration of the instance. Maximum Memory: The unit is GB, each adjustment is 2 GB, with a maximum of twice the initial memory configuration of the instance.
   Effective Policy	Select an effective policy. Immediately. Within Maintenance Window, which means the feature takes effect during the instance's Maintenance Window. You can view and configure the Maintenance Window in the Configuration Information section. Note When the Assured Serverless feature takes effect, if the current host resources are tight, instance migration (to an idle host) may occur, causing a transient connection of no more than 30 seconds. Therefore, we recommend that you configure the effective time during off-peak business hours.
   Upgrade Threshold	The CPU Threshold and Memory Threshold for elastic scale-out. When the CPU or memory usage of the instance exceeds the set threshold, the system automatically scales out the CPU and memory of the instance to the upper limit specifications. Note When the CPU or memory usage of the instance exceeds the scale-up threshold, Assured Serverless will directly scale up to the set specification upper limit, while Serverless instances adjust instance specifications in steps according to load fluctuations.
   Downgrade Threshold	The CPU Threshold and Memory Threshold for elastic scale-in. During the scale-in observation period (90 seconds), when both the CPU and memory usage of the instance are lower than the set thresholds, the system will automatically scale in the CPU and memory of the instance to the initial specifications in steps (CPU decreases by 1 core, memory decreases by 2 GB). If during the observation period, the CPU or memory usage of the instance exceeds the set Upgrade Threshold, the system will maintain or scale out the CPU and memory of the instance to the set upper limit specifications until the memory and CPU usage of the instance meet the Downgrade Threshold again.

4. Click OK.