RDS for MySQL Single-Node Instances

This section describes the architecture, advantages, and scenarios of RDS for MySQL single-node instances.

Introduction

A single-node architecture is less expensive than a primary/standby DB pair. If a fault occurs on a single-node instance, the instance cannot recover in a timely manner.

Table 1 lists the technical specifications supported by different RDS for MySQL instance types.

Advantages

For single-node instances, you can create read replicas and query error logs and slow query logs. 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, restoring data will take a long time. Therefore, single-node DB instances are not recommended for workloads that are highly sensitive to database availability.

Scenarios

Personal learning
Microsites
Development and testing environment of small- and medium-sized enterprises

Function Comparison

**Table 1** Comparison of basic functions
Item	Single-Node	Primary/Standby
Number of nodes	1	2 (default) By default, a primary/standby instance consists of two nodes (one primary and one standby). You can create read replicas if needed.
Standby node readable	N/A	No
Address type	Read/write address	Read/write address
Primary/standby replication mode	N/A	Asynchronous and semi-synchronous
Maximum number of tolerable faulty nodes	0	1
Multi-AZ DR	N/A	Supported
Specifications	vCPUs: a maximum of 128 Memory: a maximum of 1,024 GB Storage: a maximum of 4,000 GB Final specifications on the console may differ slightly.	vCPUs: a maximum of 128 Memory: a maximum of 1,024 GB Storage: a maximum of 4,000 GB Final specifications on the console may differ slightly.
Monitoring and alarms	Supported	Supported
Security group	Supported	Supported
Backup and restoration	Supported	Supported
Parameter settings	Supported	Supported
SSL	Supported	Supported
Log management	Supported	Supported
Read replicas (which need to be created)	Supported	Supported
Read/write splitting	Supported	Supported
SQL audit	Supported	Supported
DBA Assistant	Supported	Supported
Monitoring by Seconds	Supported	Supported
Failover	Not supported	Supported
Standby DB instance migration	Not supported	Supported
Manual primary/standby switchover	Not supported	Supported
Instance class change	Supported	Supported
Storage scale-up	Supported	Supported
Recycle bin	Supported	Supported