This topic provides an overview of ApsaraDB RDS for SQL Server and describes the related concepts.

ApsaraDB for RDS is a stable, reliable, and scalable online database service. It is designed based on the Apsara Distributed File System and high-performance SSD storage media of Alibaba Cloud. It supports five database engines: MySQL, SQL Server, PostgreSQL, and MariaDB. It also provides a complete suite of solutions for various scenarios, such as disaster recovery, backup, restoration, monitoring, and migration. These solutions facilitate database operation and maintenance (O&M). For more information about the benefits of ApsaraDB for RDS, see Competitive advantages of ApsaraDB RDS instances over self-managed databases.

You can submit a ticket if you require technical support. If your workloads are complex, you can purchase a support plan on the Alibaba Cloud After-Sales Support page. This allows you to seek advice from instant messaging (IM) enterprise groups, technical account managers (TAMs), and service managers.

For more information about ApsaraDB for RDS, visit the ApsaraDB RDS for MySQL product page.


Some features or functions that are described in this document may be unavailable. For more information, see the specific terms and conditions in your commercial contract. This document serves as a user guide that is for reference only. No content in this document can constitute any expressed or implied warranty.

ApsaraDB RDS for SQL Server

ApsaraDB RDS for SQL Server is built on top of a high-availability architecture and supports the restoration of data to a specific point in time. These highlights enable ApsaraDB RDS for SQL Server to support various enterprise applications. In addition, ApsaraDB RDS for SQL Server includes Microsoft-issued licenses, which eliminates the need to purchase licenses and reduces costs.
Note The license for an ApsaraDB RDS for SQL Server instance is approved based on the number of cores that are configured for the instance. You do not need to obtain a client access license.
ApsaraDB RDS for SQL Server provides the following advanced features:
  • ApsaraDB for MyBase dedicated clusters: An ApsaraDB for MyBase dedicated cluster consists of multiple hosts, such as Elastic Compute Service (ECS) instances of the ecs.i2.xlarge instance type and ECS Bare Metal instances. You can deploy RDS instances on these hosts based on your varying business requirements. For more information, see What is ApsaraDB for MyBase?
  • Disk encryption: This feature encrypts the entire data disks of your RDS instance based on block storage. Your data cannot be accessed even if data leaks occur. For more information, see Configure disk encryption for an ApsaraDB RDS for SQL Server instance. This feature does not interrupt your workloads. You can use this feature without the need to modify your application.
  • Read-only RDS instances: If the number of read requests that your database system needs to process is significantly greater than the number of write requests, a single primary RDS instance may not be able to efficiently process read requests and your workloads may be interrupted. To offload read requests from the primary RDS instance, you can create one or more read-only RDS instances. For more information, see Create a read-only ApsaraDB RDS for SQL Server instance. This way, you can increase the read capability of your database system and increase the throughput of your application.
  • Read/write splitting: After read-only RDS instances are created, you can enable the read-only routing endpoint and add the endpoint of the primary RDS instance and the read-only routing endpoint to your application. Your database system forwards write requests to the primary RDS instance and read requests to the read-only routing endpoint. Then, the read-only routing endpoint forwards the read requests to the read-only RDS instances based on the read weights of the read-only RDS instances. For more information, see Overview of read/write splitting.

For more information about the features that are supported by ApsaraDB RDS for SQL Server, see SQL Server 2019.

Basic terms

  • Instance: An RDS instance is a database process that consumes independent physical memory resources. You can specify a specific memory size, disk capacity, and database type for an RDS instance. The performance of an RDS instance varies based on the specified memory size. After an RDS instance is created, you can change its specifications or delete the instance.
  • Database: A database is a logical unit that is created on an RDS instance. One RDS instance can have multiple databases. Each database must have a unique name on the RDS instance where it is created.
  • Region and zone: Each region is a physical data center. Each region contains a number of isolated locations that are known as zones. Each zone has an independent power supply and network. For more information, visit the Alibaba Cloud's Global Infrastructure page.

General terms

Term Description
On-premises database A database that is deployed in an on-premises data center or a database that is not deployed on an ApsaraDB for RDS instance.
ApsaraDB RDS for XX (XX represents one of the following database engines: MySQL, SQL Server, PostgreSQL, and MariaDB.) ApsaraDB for RDS with a specific database engine. For example, ApsaraDB RDS for MySQL indicates an ApsaraDB for RDS instance that runs MySQL.