DB Instance Introduction

Currently, RDS DB instances are classified into the following types:

Different series support different DB engines and instance specifications.

**Table 1** DB instance types
DB Instance Type	Description	Scenarios
Single	Uses a single-node architecture. More cost-effective than the mainstream primary/standby DB instances.	Personal learning Microsites Development and testing environment of small- and medium-sized enterprises
Primary/Standby	Uses an HA architecture with one master node and one slave node. The primary and standby DB instances share the same IP address and can be deployed in different AZs.	Production databases of large- and medium-sized enterprises Applications for the Internet, Internet of Things (IoT), retail e-commerce sales, logistics, gaming, and other industries
Cluster	Uses the Microsoft Always On architecture with one master node, one slave node, and up to five read-only nodes. It features higher availability, reliability, and scalability.	Finance industry Internet industry Hotel industry Online education