Redis configuration (IV) -- cluster

Redis colony

Problem solved ：

1. Not enough capacity
2. Concurrent write operations

colony ：

• Redis The cluster has realized to Redis Horizontal expansion of , That is to start N individual redis node , The entire database is distributed and stored here N A node in the , Each node stores the total data 1/N
• Redis Clusters are partitioned （partition） To provide a certain degree of usability （availability）： Even if some nodes in the cluster fail or fail to communicate , The cluster can also continue to process command requests .

Set up the cluster

Omit here 6 individual redis Cluster configuration .
Set up redis-trib You can see ,redis Automatically set it for us 3 Lord 3 Configuration from .

Set... In the cluster k-v：

After we set up the cluster , Just log in to one of the clients .

Log in to 6379, Set a value , You can see k The slots set are 12706, This k-v Be stored in 6381 The server is up .

The server with the value will be switched to the corresponding server .


example ：aa and aaa All in group user in ：

redis cluster How to allocate these six nodes ：

slot slot：

Query the values in the cluster ：

Fault recovery ：

1. If the master node goes offline ？ Whether the slave node can be automatically promoted to the master node ？
   answer ： The slave node will be automatically promoted to the master node
   close 6381, View the cluster node information ：cluster nodes
   
2. After the primary node is restored , How about the master-slave relationship ？
   answer ： The original master node will become a slave node
   recovery 6381, View the cluster node information
   
3. If the master and slave nodes in the slot at one end are all down ,redis Whether the service can continue ？
   answer ： Then the slot in that place won't work
   close 6381 and 6391,
   
   Try to get downtime redis The content in ：
   

Set all slot Services can only be provided externally when they are normal ：