Product Series

TaurusDB for PostgreSQL instances are classified into the following types:

**Table 1** DB instance types
DB Instance Type	Description	Notes	Scenarios
Single-node	A single-node architecture is more cost-effective than a primary/standby DB pair.	If a fault occurs on a single-node instance, the instance cannot recover in a timely manner.	Personal learning Microsites Development and testing environment of small- and medium-sized enterprises
Primary/Standby	An HA architecture. A pair of primary and standby 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 the primary instance fails, a failover occurs, during which database connection is interrupted. If there is a replication delay between the primary and standby instances, the failover takes an extended period of time. The client needs to be able to reconnect to the instance.	Production databases of large and medium enterprises Applications for the Internet, Internet of Things (IoT), retail e-commerce sales, logistics, gaming, and other industries

Single-node instances: Different from primary/standby instances that have two database nodes, a single-node instance has only one node, reducing the price to half of a primary/standby instance. If the node fails, the restoration will take a long time. Therefore, single-node instances are not recommended for workloads that are highly sensitive to database availability.
Primary/Standby instances: use the standby database node only for failover and restoration. The standby database node does not provide services. If the primary node fails, the standby node can take over services immediately. Since standby nodes cause extra performance overhead, the performance of single-node instances is similar to or even higher than primary/standby instances.