redis主从搭建

╰+攻爆jí腚メ 2022-12-21 10:51 79阅读 0赞

备注:测试版本 redis 4.0.9

### 文章目录 ###

*  一.redis主从概述
 *  二.redis主从搭建
 *  参考

# 一.redis主从概述 #

Redis主从同步。数据可以从主服务器向任意数量的从服务器上同步，从服务器可以是关联其他从服务器的主服务器。这使得Redis可执行单层树复制。存盘可以有意无意的对数据进行写操作。由于完全实现了发布/订阅机制，使得从数据库在任何地方同步树时，可订阅一个频道并接收主服务器完整的消息发布 记录。同步对读取操作的可扩展性和数据冗余很有帮助。

工作原理：

Redis的主从结构可以采用一主多从或者级联结构，Redis主从复制可以根据是否是全量分为全量同步和增量同步。

全量同步  
　　Redis全量复制一般发生在Slave初始化阶段，这时Slave需要将Master上的所有数据都复制一份。具体步骤如下：  
　　1）从服务器连接主服务器，发送SYNC命令；  
　　2）主服务器接收到SYNC命名后，开始执行BGSAVE命令生成RDB文件并使用缓冲区记录此后执行的所有写命令；  
　　3）主服务器BGSAVE执行完后，向所有从服务器发送快照文件，并在发送期间继续记录被执行的写命令；  
　　4）从服务器收到快照文件后丢弃所有旧数据，载入收到的快照；  
　　5）主服务器快照发送完毕后开始向从服务器发送缓冲区中的写命令；  
　　6）从服务器完成对快照的载入，开始接收命令请求，并执行来自主服务器缓冲区的写命令；

增量同步  
　　增量同步是初始化完成后，后面的变化都通过增量同步。

# 二.redis主从搭建 #

<table> 
 <thead> 
  <tr> 
   <th>服务器类别</th> 
   <th>IP</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>主</td> 
   <td>10.31.1.123</td> 
  </tr> 
  <tr> 
   <td>从</td> 
   <td>10.31.1.124</td> 
  </tr> 
 </tbody> 
</table>

此时123、124两台已经安装了redis并已启动

**修改从库124配置文件,并重启从库**

-- masterauth  主库的redis的密码是123456
    [root@10-31-1-124 ~]# vi /usr/local/redis/redis.conf 
    # slaveof <masterip> <masterport>
    slaveof 10.31.1.123 6379
    masterauth 123456
    [root@10-31-1-124 ~]# redis-cli -a "123456" shutdown
    [root@10-31-1-124 ~]# 
    [root@10-31-1-124 ~]# redis-server /usr/local/redis/redis.conf &
    [1] 11739
    [root@10-31-1-124 ~]# 11739:C 03 Nov 17:05:25.984 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
    11739:C 03 Nov 17:05:25.985 # Redis version=4.0.9, bits=64, commit=00000000, modified=0, pid=11739, just started
    11739:C 03 Nov 17:05:25.985 # Configuration loaded
    
    [1]+  完成                  redis-server /usr/local/redis/redis.conf
    [root@10-31-1-124 ~]#

查看主库日志:

19816:M 03 Nov 17:29:30.250 * Slave 10.31.1.124:6379 asks for synchronization
    19816:M 03 Nov 17:29:30.250 * Full resync requested by slave 10.31.1.124:6379
    19816:M 03 Nov 17:29:30.250 * Starting BGSAVE for SYNC with target: disk
    19816:M 03 Nov 17:29:30.252 * Background saving started by pid 20004
    20004:C 03 Nov 17:29:30.256 * DB saved on disk
    20004:C 03 Nov 17:29:30.257 * RDB: 6 MB of memory used by copy-on-write
    19816:M 03 Nov 17:29:30.280 * Background saving terminated with success
    19816:M 03 Nov 17:29:30.280 * Synchronization with slave 10.31.1.124:6379 succeeded

查看从库日志:

11800:S 03 Nov 17:29:30.246 * DB loaded from append only file: 0.000 seconds
    11800:S 03 Nov 17:29:30.246 * Ready to accept connections
    11800:S 03 Nov 17:29:30.246 * Connecting to MASTER 10.31.1.123:6379
    11800:S 03 Nov 17:29:30.246 * MASTER <-> SLAVE sync started
    11800:S 03 Nov 17:29:30.246 * Non blocking connect for SYNC fired the event.
    11800:S 03 Nov 17:29:30.247 * Master replied to PING, replication can continue...
    11800:S 03 Nov 17:29:30.247 * Partial resynchronization not possible (no cached master)
    11800:S 03 Nov 17:29:30.252 * Full resync from master: eb10cb1b935a07e1d9c6d3b8e735e8372257fe9c:0
    11800:S 03 Nov 17:29:30.278 * MASTER <-> SLAVE sync: receiving 246 bytes from master
    11800:S 03 Nov 17:29:30.279 * MASTER <-> SLAVE sync: Flushing old data
    11800:S 03 Nov 17:29:30.279 * MASTER <-> SLAVE sync: Loading DB in memory
    11800:S 03 Nov 17:29:30.280 * MASTER <-> SLAVE sync: Finished with success
    11800:S 03 Nov 17:29:30.281 * Background append only file rewriting started by pid 11804
    11800:S 03 Nov 17:29:30.306 * AOF rewrite child asks to stop sending diffs.
    11804:C 03 Nov 17:29:30.306 * Parent agreed to stop sending diffs. Finalizing AOF...
    11804:C 03 Nov 17:29:30.306 * Concatenating 0.00 MB of AOF diff received from parent.
    11804:C 03 Nov 17:29:30.306 * SYNC append only file rewrite performed
    11804:C 03 Nov 17:29:30.307 * AOF rewrite: 6 MB of memory used by copy-on-write
    11800:S 03 Nov 17:29:30.346 * Background AOF rewrite terminated with success
    11800:S 03 Nov 17:29:30.346 * Residual parent diff successfully flushed to the rewritten AOF (0.00 MB)
    11800:S 03 Nov 17:29:30.346 * Background AOF rewrite finished successfully

查看redis复制信息

[root@10-31-1-123 redis]# redis-cli -a 123456
    127.0.0.1:6379> info replication
    # Replication
    role:master
    connected_slaves:1
    slave0:ip=10.31.1.124,port=6379,state=online,offset=6451,lag=1
    master_replid:0976d29309e95ba0b109945c001a8391d1d67e53
    master_replid2:0000000000000000000000000000000000000000
    master_repl_offset:6451
    second_repl_offset:-1
    repl_backlog_active:1
    repl_backlog_size:1048576
    repl_backlog_first_byte_offset:1
    repl_backlog_histlen:6451

**自此，redis的主从就已经搭建完成**

# 参考 #

1.https://blog.csdn.net/weixin\_42711549/article/details/83061052