Crazy God redis notes 11

 

 

append：

We can also configure in our configuration file ：

 

 

We don't open it by default .

  Let's change it to yes：

Just doing this step will open our aof.

 

We delete the previous rdb.

Restart our redis after ：

 

 

 

 

 

  If the file is normal , restart redis You can recover .

Finally, remember to modify the file we modified .

Rewriting rule （ Understanding can ）：
 

aof The default is unlimited file append , The file will get bigger and bigger ！

If aof File is larger than 64m, It's too big ！fork A new process to rewrite our files .

 

In master-slave replication ,rdb It's a spare ！

Expand ：

 

 

 redis Subscription Publishing ：

 

 

 

So let's test that out ：

Now let's create a subscriber ：

 

Then we create a publisher at another terminal ：

 

 

After we release , We can see the information just released here .

 

 

 

We can understand this part . In the future, the message is mq To do it .

 redis Cluster environment construction ：

 

 

We only have such a configuration file now , We will open three configuration files later redis service , Make a sense of pseudo cluster .

Next, let's configure the environment ：
Only configure slave Libraries , No need to configure the main library .

We can view the information of the current library ：

 

We can see that it is a host , No slave .

Now let's configure , We're going to open it 4 Terminals , Three are used for service , One for testing ：

 

We copied it first 3 Configuration files .

Let's change our 79 Configuration file for ：

 

 

Our first library is to change the log file name and rdb file name .

80 The configuration file ：

We need to change its port first ：

 

 

 

 

Finally, let's put it in the same way 81 Just change your configuration file .

Now let's summarize what we have modified ：

 

We are now carrying out single machine multi service , If you have conditions, you can try multi machine and multi service ：

Now let's turn on all three .

 

At present, we can see that our three services have been set up .

Now we have forged one The pseudo cluster mode of one master and two slaves .

 

Now our three are hosts .

By default , Each station redis Servers are all primary nodes .  Generally, we only need to configure the slave .

Recognize the boss ！ One master and two subordinates . Here we let our 79 Bit host . So we only need to configure the slave ：

We can see it role It has become a slave . And you can see its corresponding host port number and host address .

  Let's take a look at the information changes in the host ;

We can also see the information of the above slave .

We put 81 Just do the same configuration .

  The real master-slave configuration should be configured in the configuration file , It's permanent , Here we use commands to configure , Is temporary .

details ：

The host can write , The slave can't write, only read ！ All the information and data in the host , Will be automatically saved by the slave machine .

I set the value in the host .

 

We can also get the value set by the host in the slave .

 

And you can see that the slave can only read but not write .

 

Our host is now turned off .

 

Our slave is still normal .

 

And we can still get the value .

Let's restart the host ：

 

 

We can still get our value .

test ： The host is disconnected , The slave can still connect to the host . But there is no write operation , This is the time , If the mainframe comes back , The slave can still get the information written by the host directly ！

But there are some unreasonable places in this place , Our host is down , You should choose a new slave as the host , We'll solve this later .

What if our slave is disconnected ？

 

We have only one slave left now .

 

The host writes a message .

  At this time, we turn on the just broken slave again ：

The written information in the host cannot be obtained .

 

Now we can see our original 80 At this time, the slave of the port has become the host , If not configured in the configuration file , It is the host .

If it's a master-slave configured using the command line , At this time, if you restart , Will become a host ！

  So let's think about it , If we use the command line now , Configure it as a slave and connect it to our host ？

 

It has become a slave .

 

We can get the value again .

Just change back to the slave , We can get the data in our host immediately ！