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	Notes	Scenarios
Single	Uses a single-node architecture. More cost-effective than the mainstream primary/standby DB instances.	If a fault occurs on a single instance, the instance cannot recover in a timely manner.	Personal learning Microsites Development and testing environment of small- and medium-sized enterprises
Primary/Standby	Uses an HA architecture. A pair of primary and standby DB instances shares the same IP address and can be deployed in different AZs.	When a primary instance is being created, a standby instance is provisioned synchronously to provide data redundancy. The standby instance is invisible to you after being created. If a failover occurs due to a primary instance failure, your database client will be disconnected for a short period of time. You need to reconnect the client to the instance.	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