This topic describes ApsaraDB RDS for SQL Server instances of the Basic Edition.
ApsaraDB RDS for SQL Server Basic Edition is a cost-effective, single-node instance that uses a compute-storage separation architecture.
A Basic Edition instance has a single database node and no secondary node for hot backup. Consequently, the instance may be unavailable for an extended period during unexpected downtime or when you perform tasks such as restarting the instance, changing specifications, or upgrading the version. If your business requires high database availability, we recommend that you do not use the Basic Edition. Instead, you can choose another edition, such as the High-availability Edition. Some Basic Edition instances can also be upgraded to the High-availability Edition.
On the instance details page, in the Basic Information section, the Type and Edition field is Regular Instance (Basic Edition).
The following diagrams show the architectures of the Basic Edition and High-availability Edition.
Benefits
Performance
Because there is no secondary node, the primary node does not incur performance overhead from real-time database replication. As a result, the Basic Edition can offer better performance than a High-availability Edition instance with the same specifications.
Reliability
The separation of compute and storage ensures that failures on the compute node do not cause data loss.
NoteIf you set the Log Backup Frequency for a Basic Edition instance to Every 30 minutes, you may lose up to 30 minutes of data in extreme cases, such as a completely damaged underlying cloud disk or other catastrophic failures. You can restore the instance to the point in time of the last successful log backup. For instructions on how to configure this setting, see Back up SQL Server data.
Multiple replicas stored on Apsara Distributed File System, Alibaba Cloud's large-scale distributed storage system, ensure data reliability.
Cost
By using a single database node, this edition significantly reduces costs, with prices as low as half that of the High-availability Edition.
Features
The Basic Edition supports fundamental features such as IP address whitelist, monitoring and alerting, and backup and recovery. However, it does not support the following features:
For a complete list of supported features, see SQL Server feature overview.
Use cases
Small-scale websites or applications
Purchase a highly cost-effective cloud database to offload database O&M and focus on your core business.
Personal learning
The Basic Edition is ideal for beginners to test and learn about databases.
Development and testing
Use the rapid provisioning capabilities of our cloud database to create and release resources on demand, significantly improving development efficiency.
Purchase and use an instance
Follow the quick start guide to purchase a Basic Edition instance and connect to the SQL Server database. For details, see Quickly create and use an ApsaraDB RDS for SQL Server instance.
Upgrade to the High-availability Edition
You can upgrade ApsaraDB RDS for SQL Server Basic Edition instances to the High-availability Edition. For more information, see Upgrade an ApsaraDB RDS for SQL Server instance from Basic Edition to High-availability Edition.
After you upgrade to the High-availability Edition, you cannot directly downgrade the instance back to the Basic Edition. However, you can purchase a new Basic Edition instance, migrate data to a new instance, and then release the original instance.
FAQ
Why is it slow to upgrade or change the specifications of a Basic Edition instance?
A Basic Edition instance runs on a single node. When you upgrade the instance or change its specifications, the system checks if the current physical server has sufficient resources. If resources are insufficient, the system replicates the node's data to another physical server and then performs a switchover. In extreme cases, this process can cause an outage of more than 30 minutes. We recommend using the High-availability Edition or Cluster Edition. These editions use a high-availability architecture with a secondary instance that can take over during the upgrade. This architecture minimizes service impact and results in shorter downtime.
Why are some features unavailable for the Basic Edition? What features does it support?
Due to its single-node architecture, the Basic Edition is not suitable for certain business scenarios. Therefore, its feature set differs from that of the High-availability and Cluster editions. For a detailed comparison of features across different editions, see SQL Server feature overview.