TencentDB for MySQL supports four types of architectures: single-node, two-node, three-node,and Cluster Edition. This document describes the two-node architecture.
Note
TencentDB for MySQL two-node instances are built on a one-source-one-replica architecture, with the source only providing access and the replica serving as disaster recovery system alone.
Two-node instances are built on a highly available one-source-one-replica architecture that implements real-time hot backup, automatic failure detection, and automatic failover.
Two-node instances support two resource isolation policies: general and dedicated. For more information, see Resource Isolation Policy.
Use Cases
They are widely used in a variety of industries, including gaming, the internet, IoT, retail, e-commerce, logistics, insurance, and securities.
Features
The two-node architecture offers two source/replica replication modes: async (default) and semi-sync. You can modify the replication mode on the instance details page in the console. Or you can do so when upgrading to the three-node architecture as instructed in Upgrading Two-Node Instances to Three-Node Instances.
The three-node architecture supports a complete set of features including read-only instances, disaster recovery instances, security groups, data migration, and multi-AZ deployment. For more information, see Strengths.
Achieves a high availability of up to 99.95%. For more information, see Service Level Agreement.
The two-node instance provides multiple replicas to guarantee data persistence. The source node data can be synced to the replica node; the source instance data can be synced to the read-only instances (if any). This architecture ensures data security and achieves a data persistence of up to 99.99999% (seven nines).
The two-node architecture deploys data nodes on powerful hardware devices and uses local NVMe SSD disks as underlying storage with an IOPS of up to 240,000. This value is the test result with MySQL's default page size of 16 KB and for your reference only. The actual value is subject to the specific configuration, page size, and business load.
Basic Framework Diagram
Upgrading
The engine versions of TencentDB for MySQL can be upgraded. For more information, see Upgrading Database Engine.
