Billing Overview
RDS is the abbreviation of Relational Database Service. It is an out of the box, stable, reliable, and elastic online database service. It has multiple security protection measures and perfect performance monitoring system, and provides professional database backup, recovery and optimization solutions, enabling you to focus on application development and business development. RDS supports the following database engines：MySQL; SQL Server; PostgreSQL. The following is an overview of RDS for SQL Server charging rule:
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The relationship between billing item and billing method is as below:
| Billing Item | Description | Billing Method |
|---|---|---|
| Main Instance Type | Charged based on the instance type. The instance type determines the number of vCPUs and the size of memory of the SQL Server main instance. | Pay-As-You-Go, Subscription |
| Read Only Instance Type | Charged based on the instance type. The instance type determines the number of vCPUs and the size of memory of the SQL Server read only instance. | Pay-As-You-Go, Subscription |
| Cloud SSD Storage | Charged based on the Storage capacity. The Storage capacity determines the size of Cloud SSD. | Pay-As-You-Go, Subscription |