Redis getting started complete tutorial: replication topology

Redis The replication topology can support single-layer or multi-layer replication relationships , According to the topological complexity
It can be divided into the following three categories ： A master from 、 One master, many followers 、 Tree master slave structure , Here are the introduction .
1. One master and one slave structure
A master-slave structure is the simplest replication topology , Used for the slave node when the master node goes down
Provide failover support （ Pictured 6-4 Shown ）. When the concurrency of application write command is high and needs to be persistent
Chemical time , It can only be turned on from the node AOF, This not only ensures data security, but also avoids persistent
Jiuhua interferes with the performance of the primary node . But it should be noted that , When the master node turns off the persistence function ,
If the primary node is offline, avoid automatic restart operation . Because the master node has not enabled the persistence function before
Data set is empty after auto restart , At this time, if the slave node continues to copy the master node, it will cause the slave node data
Also emptied , Lost the meaning of permanence . The safe way to do this is to execute... On the slave node
slaveof no one Disconnect the replication relationship with the primary node , Restart the main

Nodes to avoid this problem .

 

2. One master multi slave structure
One master multi slave structure （ Also known as star topology ） This enables the application side to utilize multiple slave nodes
Read and write separation （ See the picture 6-5）. For scenes where reading takes up a large proportion , You can send a read command to
From the node to share the pressure of the main node . At the same time, in daily development, if you need to implement some time-consuming
Read command , Such as ：keys、sort etc. , It can be executed on one of the slave nodes , Prevent slow query pairs
The main node causes congestion, which affects the stability of online services . For scenarios with high write concurrency , many
A slave node will cause the master node to write commands to send slave nodes many times  

        

3. Tree master slave structure
Tree master slave structure （ Also known as tree topology ） So that the slave node can not only copy the master node
data , At the same time, it can continue to replicate to the next level as the master of other slave nodes . By introducing replication
Stroma , It can effectively reduce the load of the master node and the amount of data to be transmitted to the slave node . Pictured 6-6 the
in , Data write node A It will be synchronized to B and C node ,B The node synchronizes the data to D and E section
spot , Data is replicated layer by layer . When the master node needs to mount multiple slave nodes, in order to
Avoid performance interference to the primary node , Tree structure can be used to reduce the pressure of the main node .