主库产生RDB以及缓存呼吁到从库:
- 33565:M 26 Aug 2019 11:54:48.918 * Replica 127.0.0.1:6380 asks for synchronization
- 33565:M 26 Aug 2019 11:54:48.918 * Partial resynchronization not accepted: Replication ID mismatch (Replica asked for 'fc71b19242e8145254ba7751d346a8f4bb4c53c6', my replication IDs are '1e531f295fc2dcf986a18889e8f8c3b6e6fdc7b6' and '0000000000000000000000000000000000000000')
- 33565:M 26 Aug 2019 11:54:48.918 * Starting BGSAVE for SYNC with target: disk
- 33565:M 26 Aug 2019 11:54:48.919 * Background saving started by pid 33574
- 33574:C 26 Aug 2019 11:54:48.929 * DB saved on disk
- 33574:C 26 Aug 2019 11:54:48.929 * RDB: 4 MB of memory used by copy-on-write
- 33565:M 26 Aug 2019 11:54:49.002 * Background saving terminated with success
- 33565:M 26 Aug 2019 11:54:49.003 * Synchronization with replica 127.0.0.1:6380 succeeded
场景二,间断后同步
假如因为某种妨碍导致了从数据库停息了与主数据库的同步后,从数据库从头毗连到主数据库,主数据库只必要将间断时代执行的呼吁传送到从库(基于呼吁记录名目),这样就可以继承举办同步,保持数据同等性。
注:该殊效在Redis 2.8版本后实现,2.6版本之前均必要从头初始化。
浅显进程如下:
(1) 模仿从库间断,将其kill掉
- [redis@albert src]$ ps -ef | grep redis
- redis 33565 33500 0 11:54 pts/4 00:00:01 ./redis-server *:6379
- redis 33570 33476 0 11:54 pts/5 00:00:01 ./redis-server 127.0.0.1:6380
- redis 33744 33688 0 12:03 pts/0 00:00:00 ./redis-server 127.0.0.1:6382
- [redis@albert src]$
- [redis@albert src]$ kill -9 33744
(2) 主库吸取到间断信息
- 33565:M 26 Aug 2019 12:03:17.736 * Replica 127.0.0.1:6382 asks for synchronization
- 33565:M 26 Aug 2019 12:03:17.736 * Partial resynchronization request from 127.0.0.1:6382 accepted. Sending 714 bytes of backlog starting from offset 1.
- 33565:M 26 Aug 2019 12:13:43.494 # Connection with replica 127.0.0.1:6382 lost.
(3) 按照偏移量举办同步
- 33565:M 26 Aug 2019 12:14:12.019 * Replica 127.0.0.1:6382 asks for synchronization
- 33565:M 26 Aug 2019 12:14:12.019 * Partial resynchronization request from 127.0.0.1:6382 accepted. Sending 436 bytes of backlog starting from offset 1315.
场景三,增量复制
因为Redis同步的是呼吁荟萃,主数据库记录那些对本身状态产生改观的指令记录到当地内存buffer中,通过异步的方法将buffer中的指令同步到从数据库,从数据库操作这些指令执行,以保持与主数据库一样的状态,也等于通过应用呼吁的偏移量反馈到主数据库,让主数据库不绝发送buffer指令。
偏移量的查察:
- role:master
- connected_slaves:2
- slave0:ip=127.0.0.1,port=6380,state=online,offset=3724,lag=1
- slave1:ip=127.0.0.1,port=6382,state=online,offset=3724,lag=1
- master_replid:b9e0f41a523e078a6a88ae274f204777775ab4dc
- master_replid2:0000000000000000000000000000000000000000
- master_repl_offset:3724
- second_repl_offset:-1
- repl_backlog_active:1
- role:slave
- master_host:127.0.0.1
- master_port:6379
- master_link_status:up
- master_last_io_seconds_ago:7
- master_sync_in_progress:0
- slave_repl_offset:3752
- slave_priority:100
- slave_read_only:1
四、数据同等性验证
Redis提供了两种数据同步模式,以保持主数据库与从数据库的同等性。
完备性同步,也就是上文说到的数据初始化进程,将主数据库中所存储的全部数据所有发送到从数据库。
部门同步,对应着上文说起的增量复制,即只将部门数据发送到从数据库。
1. 测试验证
增进从库实例
- [redis@albert src]$ cp redis.conf6380 redis.conf6382
调解设置文件 (编辑:湖南网)
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