Real-Time Disaster Recovery

Precautions

The performance indicators provided in this section are for reference only. The actual environment is affected by factors such as the performance of the source or destination database, network bandwidth, data model, and service model.

Specification Description

Based on the performance of data flow types, there are four types of specifications: micro, small, medium, and large. Table 1 lists the performance upper limit of each specification.

**Table 1** Performance upper limit
Specifications	Reference Values of Maximum Performance (Rows/Second)
Micro	300
Small	3000
Medium	7500
Large	10000

The performance of each specification is affected by factors such as the networks, service and DR database performance, and latency. The values in the table are for reference only.
DRS provides specifications of different performance which is measured by DR initialization (no flow control) and DR performance.
The maximum performance (row/second) is measured by the number of transactions synchronized per second. The statement types include BEGIN, COMMIT, DML (INSERT, DELETE, and UPDATE), and DDL. You can view the destination database write frequency (apply_rows_rate) monitoring metric on Cloud Eye.
DRS allows you to upgrade specifications only for DR tasks from MySQL to MySQL, MySQL to GaussDB(for MySQL), and GaussDB(for MySQL) to GaussDB(for MySQL). Task specifications cannot be downgraded. For details, see Changing Specifications.
If you want to compare values for a DRS task, select large specifications when creating the DRS task.

Multiple Specifications

DRS real-time DR allows you to select specifications for some specified data flow tasks.

**Table 2** Data types that support multiple specifications
DR Direction	Data Flow	Multiple Specifications	Specification Upgrade
Current cloud as standby	MySQL->MySQL	Supported	Yes
Current cloud as active	MySQL->MySQL	Supported	Yes
Current cloud as standby	MySQL->GaussDB(for MySQL)	Supported	Yes
Current cloud as standby	DDM -> DDM	Unsupported	No
Current cloud as active	DDM -> DDM	Unsupported	No
Current cloud as standby	GaussDB(for MySQL)->GaussDB(for MySQL)	Supported	Yes
Current cloud as active	GaussDB(for MySQL)->GaussDB(for MySQL)	Supported	Yes
Dual-active DR	MySQL->MySQL	Supported	Yes
Dual-active DR	GaussDB(for MySQL)->GaussDB(for MySQL)	Supported	No