You can use a deployment set to distribute RDS Custom instances across different physical servers. This ensures high availability for your business applications and enhances the disaster recovery capabilities of the underlying physical servers. You can also use a deployment set to deploy RDS Custom instances within the same network topology to reduce latency between the instances and improve application performance. This topic describes how to create an RDS Custom deployment set.
Prerequisites
Before you create a deployment set, review the Limits to understand the restrictions on RDS Custom instances and deployment sets, including their region and zone limits.
Procedure
Log on to the ApsaraDB RDS console. In the navigation pane on the left, click RDS Custom > Deployment Sets. Then, select a region at the top of the page.
On the Deployment Sets page, click Create Deployment Set.
In the Create Deployment Set dialog box, enter the Deployment Set Name.
Select an Emergency Solution. This solution is used when an instance is migrated due to a breakdown, but the deployment set does not have enough available physical servers to meet the distribution policy.
CancelMembershipAndStart: Removes the instance from the deployment set and starts it immediately after migration.
KeepStopped: Retains the instance's membership in the deployment set and keeps the instance in the Stopped state.
Enter a Description.
Select a Deployment Set Policy.
Deployment set policy
Description
Scenario
Maximum number of instances
HA (Availability)
All RDS Custom instances in a deployment set are strictly distributed to different physical servers in a region.
This policy is suitable for scenarios in which RDS Custom instances must be isolated from each other to prevent SPOFs.
Maximum number of RDS Custom instances per zone: 20.
Total number of RDS Custom instances in a deployment set: Number of zones × Maximum number of RDS Custom instances per zone. For example, if an Alibaba Cloud region has three zones, the deployment set supports up to 60 RDS Custom instances in the region, which is calculated by using the following formula: 3 × 20 = 60.
HA group (AvailabilityGroup)
A deployment set can be divided into up to seven groups. RDS Custom instances can be distributed to the groups of a deployment set based on your business requirements.
RDS Custom instances in different groups are strictly distributed to different physical servers in a region to prevent SPOFs.
RDS Custom instances in the same group may be deployed on the same physical server to reduce the network latency.
This policy is suitable for large-scale deployment scenarios and scenarios that require the prevention of SPOFs and low network latency between RDS Custom instances.
Maximum number of RDS Custom instances per group per zone: 20.
Maximum number of groups per zone: 7.
Total number of RDS Custom instances in a deployment set: Number of zones × Maximum number of RDS Custom instances per group per zone × Maximum number of groups. For example, if an Alibaba Cloud region has three zones, the deployment set supports up to 420 RDS Custom instances in the region, which is calculated by using the following formula: 20 × 3 × 7 = 420.
Low latency strategy (LowLatency)
All RDS Custom instances are centrally deployed in the same network topology in the same zone to reduce the network latency. In this case, multiple RDS Custom instances may be deployed to the same physical server, and HA cannot be ensured.
This policy is suitable for latency-sensitive HA application clusters.
Resources can be deployed only in one zone.
Total number of RDS Custom instances in a deployment set: 20.
Click OK.
Related APIs
Create an RDS Custom deployment set in a specified region: CreateRCDeploymentSet
Query the properties of one or more RDS Custom deployment sets: DescribeRCDeploymentSets