Updated on 2022-12-08 GMT+08:00

Function Comparison

Single DB instances use the single-node architecture. In contrast to the mainstream primary/standby DB instances, a single DB instance contains only one node and has no slave node for fault recovery.

Advantage Comparison

  • Single DB instances: supports the creation of read replicas (except for Microsoft SQL Server) and supports the queries of error logs and slow query logs. Different from primary/standby DB instances that have two database nodes, a single DB instance has only one node. If a node fails, the restoration will take a long time. Therefore, single DB instances are not recommended for sensitive services that have high requirements on database availability.
  • Primary/Standby DB instances: uses the slave database node only for failover and restoration. The slave database node does not provide services. The performance of single DB instances is similar to or even higher than the primary/standby DB instances.
Table 1 Function comparisons

DB Engine

Single

Primary/Standby

MySQL

8.0

5.7

5.6

8.0

5.7

5.6

PostgreSQL

11

10

9.6

9.5

11

10

9.6

9.5

Number of nodes

1

2

Specifications

vCPUs: a maximum of 76

Memory: a maximum of 304 GB

Storage space: a maximum of 4 TB

vCPUs: a maximum of 76

Memory: a maximum of 304 GB

Storage space: a maximum of 4 TB

Monitoring and alarms

Supported

Supported

Security group

Supported

Supported

Backups and restorations

Supported

Supported

Parameter settings

Supported

Supported

SSL

Supported

Supported

Log management

Supported

Supported

Read replicas (need to be created)

Supported

Supported

High-frequency monitoring

Supported

Supported

Primary/standby switchover or failover

Not supported

Supported

Standby DB instance migration

Not supported

Supported