What is the principle behind Redis master-slave replication?

6 months ago

2 minutes

Redis master-slave replication is achieved by synchronizing the data from the master node to the slave node to backup data and increase availability. The main principles of implementing master-slave replication include the following steps:

The subordinate node connects to the primary node by sending a SYNC command, requesting to establish a replication connection. Upon accepting the request, the primary node adds the subordinate node to its replication queue.
Snapshot synchronization: The master node sends a snapshot of its data to the slave node, which receives the data and loads it into memory, completing the initial data synchronization.
Command dissemination: The master node sends the write commands it executes to all the slave nodes, which then execute the same operation locally upon receiving the command, ensuring data consistency.
Incremental synchronization: The primary node sends the write commands it has executed to the secondary node along with the operation sequence number. The secondary node then executes the same operations based on the sequence number to achieve incremental synchronization of data.

By following the above steps, the master-slave replication achieves data backup and high availability. When the master node fails, the slave node can take over and continue providing services to ensure system availability.