（进阶篇）Redis6.2.0 集群 主从复制_原理剖析_02
2022-09-06 22:44:50

* Ready to accept connections # 准备就绪等待链接
* Replica 1xxx.xxx.xxx.101:6379 asks for synchronization
  # 102节点向主节点发起了一个全量resync 的请求
* Full resync requested by replica 1xxx.xxx.xxx.101:6379
  # 主节点创建缓冲区，
* Replication backlog created, my new replication IDs are 'b1f446c9ea7c0d5e95c8c47f31b000000000000000000000000000'
  # 通过BGSAVE 将数据写入磁盘，生成rdb快照，发给子节点
* Starting BGSAVE for SYNC with target: disk
* Background saving started by pid 11978
* DB saved on disk
  # 通过copy-on-write的方式将4m数据写入磁盘
* RDB: 6 MB of memory used by copy-on-write
* Background saving terminated with success
  # 101 节点的复制结束了 子节点加载rdb快照文件读取数据
* Synchronization with replica 1xxx.xxx.xxx.101:6379 succeeded
* Replica 1xxx.xxx.xxx.102:6379 asks for synchronization
* Full resync requested by replica 1xxx.xxx.xxx.102:6379
* Starting BGSAVE for SYNC with target: disk
* Background saving started by pid 11979
* DB saved on disk
* RDB: 4 MB of memory used by copy-on-write
* Background saving terminated with success
* Synchronization with replica 1xxx.xxx.xxx.102:6379 succeeded
# Disconnecting timedout replica: 1xxx.xxx.xxx.101:6379
# Connection with replica 1xxx.xxx.xxx.101:6379 lost.
# Disconnecting timedout replica: 1xxx.xxx.xxx.102:6379

[root@bigdata01 bin]# /usr/local/redis/bin/redis-cli -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
127.0.0.1:6379> info replication
# Replication
role:master # 角色主节点
connected_slaves:2 #它所连接到的从节点的数量
# 从节点ip地址、 端口、状态：在线 当前从节点读取命令的偏移量 延迟时间：单位:秒
#offset指的是从节点已经复制的命令偏移量是266
# 这里的offset=master_repl_offset说明主从偏移量是一致的
slave0:ip=1xxx.xxx.xxx.101,port=6379,state=online,offset=266,lag=1 #当前连接从01 slave节点信息
slave1:ip=1xxx.xxx.xxx.102,port=6379,state=online,offset=266,lag=1 #当前连接从02 slave节点信息
master_failover_state:no-failover
# 主从的id
master_replid:b1f446c9ea7c0d5e95c8c47f31bb007cea158ce8
# 主从发生变化之后id
master_replid2:0000000000000000000000000000000000000000
# 主节点会把所有的命令转换成子字节。写到队里额里面，最终写入的值就是master_repl_offset
# 主节点已写入的命令偏移量是266
master_repl_offset:266
# 判断是否全量复制的标识
second_repl_offset:-1

# 2.8之后 缓冲区
repl_backlog_active:1 # 是否开启缓冲区 1-开启 0-关闭
repl_backlog_size:1048576 # 缓冲区大小 1m，可以调控
repl_backlog_first_byte_offset:1 # 从偏移量为1开始写入
repl_backlog_histlen:266 # 当前缓存冲区长度
127.0.0.1:6379>

[root@bigdata02 ~]# /usr/local/redis/bin/redis-cli -a 123456
Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
127.0.0.1:6379> info replication
# Replication
 # 角色
role:slave
# 主节点ip
master_host:1xxx.xxx.xxx.100
# 主节点端口
master_port:6379
# 主节点当前状态
master_link_status:up
# 主从复制最后一次 4秒之前
master_last_io_seconds_ago:4
# 现在主从同步状态 0-未同步 1-正在同步
master_sync_in_progress:0
# 从节点复制的偏移量
slave_repl_offset:3xxx
# 从节点在选举时，成为主节点的权重优先级，这个参数越大，晋升主节点的优先级越高
slave_priority:100
# 从节点只读模式是否开启 1-开启 0-未开启
slave_read_only:1
# 从节点连接从节点数量
connected_slaves:0
master_failover_state:no-failover
# 连接主节点的id
#当前主节点宕机后master_replid会变成一个信心的，master_replid2存储老的主节点master_replid
master_replid:b1f446c9ea7c0d5e95c8c47f31bb007cea158ce8
master_replid2:0000000000000000000000000000000000000000
# 主节点写入的偏移量
master_repl_offset:3xxx
second_repl_offset:-1
repl_backlog_active:1
repl_backlog_size:1048576
repl_backlog_first_byte_offset:1
repl_backlog_histlen:3xxx
127.0.0.1:6379>