Mysql 主从数据库同步(centos篇)
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2023-12-18 23:13:16
环境:
主服务器:centos 5.2 mysql 5.1.35 源码 ip:192.168.1.22
从服务器:centos 5.2 mysql 5.1.35 源码&...
环境:
主服务器:centos 5.2 mysql 5.1.35 源码 ip:192.168.1.22
从服务器:centos 5.2 mysql 5.1.35 源码 ip:192.168.1.33
配置:
一、主服务器
1.1、创建一个复制用户,具有replication slave 权限。
mysql>grant replication slave on *.* to 'repl'@'192.168.1.22' identified by 'repl';
1.2、编辑my.cnf文件
vi /etc/my.cnf
添加
server-id=1
并开启log-bin二进制日志文件
log-bin=mysql-bin
添加
server-id=1
并开启log-bin二进制日志文件
log-bin=mysql-bin
注:需要把默认的server-id=1去掉
1.3、启动mysql数据库
mysqld_safe --user=mysql &
1.4、设置读锁
mysql>flush tables with read lock;
1.5、得到binlog日志文件名和偏移量
mysql>show master status;
+------------------+----------+--------------+------------------+
| file | position | binlog_do_db | binlog_ignore_db |
+------------------+----------+--------------+------------------+
| mysql-bin.0000010 | 106| | |
+------------------+----------+--------------+------------------+
| file | position | binlog_do_db | binlog_ignore_db |
+------------------+----------+--------------+------------------+
| mysql-bin.0000010 | 106| | |
+------------------+----------+--------------+------------------+
1.6、备份要同步的数据库
mysqldump test > test.sql
1.7、解锁
mysql>unlock tables;
二、从服务器
2.1、编辑my.cnf文件
vi /etc/my.cnf
添加
server-id=2
添加
server-id=2
注:需要把默认的server-id=1去掉
2.2、启动从数据库
mysqld_safe --user=mysql &
2.3、对从数据库进行相应设置
mysql> change master to
-> master_host='192.168.1.22'
-> master_user='repl'
-> master_password='repl'
-> master_log_file='mysql-bin.0000010'
-> master_log_pos=106;
-> master_host='192.168.1.22'
-> master_user='repl'
-> master_password='repl'
-> master_log_file='mysql-bin.0000010'
-> master_log_pos=106;
2.4、启动从服务器slave线程
mysql>start slave;
执行show processlist命令显示以下进程:
mysql>show processlist\g
*************************** 2. row ***************************
id: 2
user: system user
host:
db: null
command: connect
time: 2579
state: has read all relay log; waiting for the slave i/o thread to update it
info: null
表示slave已经连接上master,开始接受并执行日志
*************************** 2. row ***************************
id: 2
user: system user
host:
db: null
command: connect
time: 2579
state: has read all relay log; waiting for the slave i/o thread to update it
info: null
2.5、查看slave线程状态
mysql>show slave status;
*************************** 1. row ***************************
slave_io_state: waiting for master to send event
master_host: 192.168.1.22
slave_io_state: waiting for master to send event
master_host: 192.168.1.22
master_user: repl
master_port: 3306
connect_retry: 60
master_log_file: mysql-bin.0000010
read_master_log_pos: 106
relay_log_file: centos-relay-bin.000002
relay_log_pos: 529
relay_master_log_file: mysql-bin.0000010
slave_io_running: yes
slave_sql_running: yes
replicate_do_db:
master_port: 3306
connect_retry: 60
master_log_file: mysql-bin.0000010
read_master_log_pos: 106
relay_log_file: centos-relay-bin.000002
relay_log_pos: 529
relay_master_log_file: mysql-bin.0000010
slave_io_running: yes
slave_sql_running: yes
replicate_do_db:
replicate_ignore_db:
replicate_do_table:
replicate_ignore_table:
replicate_wild_do_table:
replicate_wild_ignore_table:
last_errno: 0
last_error:
skip_counter: 0
exec_master_log_pos: 106
relay_log_space: 830
until_condition: none
until_log_file:
until_log_pos: 0
master_ssl_allowed: no
master_ssl_ca_file:
master_ssl_ca_path:
master_ssl_cert:
master_ssl_cipher:
master_ssl_key:
seconds_behind_master: 0
master_ssl_verify_server_cert: no
last_io_errno: 0
last_io_error:
last_sql_errno: 0
last_sql_error:
1 row in set (0.00 sec)
replicate_do_table:
replicate_ignore_table:
replicate_wild_do_table:
replicate_wild_ignore_table:
last_errno: 0
last_error:
skip_counter: 0
exec_master_log_pos: 106
relay_log_space: 830
until_condition: none
until_log_file:
until_log_pos: 0
master_ssl_allowed: no
master_ssl_ca_file:
master_ssl_ca_path:
master_ssl_cert:
master_ssl_cipher:
master_ssl_key:
seconds_behind_master: 0
master_ssl_verify_server_cert: no
last_io_errno: 0
last_io_error:
last_sql_errno: 0
last_sql_error:
1 row in set (0.00 sec)
验证是否配置正确
在从服务器上执行
show slave status\g;
waiting for master to send event
slave_io_running: yes
slave_sql_running: yes
waiting for master to send event
slave_io_running: yes
slave_sql_running: yes
如以上二行同时为yes 说明配置成功
测试
1、在主服务器test数据库中创建user表
mysql>use test;
mysql>create table user(id int);
mysql>create table user(id int);
2、在从服务器中查看user表
mysql>use test;
mysql> show tables like 'user';
+----------------------+
| tables_in_test(user) |
+----------------------+
| user |
+----------------------+
1 row in set (0.00 sec)
mysql> show tables like 'user';
+----------------------+
| tables_in_test(user) |
+----------------------+
| user |
+----------------------+
1 row in set (0.00 sec)
说明主从数据同步成功。
问题?
1.在从数据库中查看slave状态时出现
the slave i/o thread stops because master and slave have equal mysql server ids; these ids must be different for replication to work (or the --replicate-same-server-id option must be used on slave but this does not always make sense; please check the manual before using it)
说明方从服务器里my.cnf中的server-id有相同的。
解决办法:
修改my.cnf里的server-id,并重启数据库服务。my.cnf文件默认有server-id=1
其它说明
主服务器my.cnf
#binlog-do-db=需要备份的数据库名,可写多行
#binlog-ignore-db=不需要备份的数据库名,可写多行
从服务器my.cnf
#binlog-ignore-db=不需要备份的数据库名,可写多行
从服务器my.cnf
# replicate-do-db=test 需要备份的数据库名
# replicate-ignore-db=mysql 忽略的数据库
# master-connect-retry=60 如果从服务器发现主服务器断掉,重新连接的时间差(秒)
# replicate-ignore-db=mysql 忽略的数据库
# master-connect-retry=60 如果从服务器发现主服务器断掉,重新连接的时间差(秒)
以下设置也可直接修改my.cnf配置文件
log-bin=mysql-bin
master-host=192.168.1.22
master-host=192.168.1.22
master-user=repl
master-password=repl
master-port=3306
master-port=3306
主从服务器同步维护
由于各种原因,导致主从数据不一致,在负载低的时候,进行手动同步.
在主服务器上执行
mysql>flush tables with read lock;
query ok,rows affected (0.01 sec)
mysql>show master status;
+------------------+----------+--------------+------------------+
| file | position | binlog_do_db | binlog_ignore_db |
+------------------+----------+--------------+------------------+
| mysql-bin.0000011 | 260| | |
+------------------+----------+--------------+------------------+
| file | position | binlog_do_db | binlog_ignore_db |
+------------------+----------+--------------+------------------+
| mysql-bin.0000011 | 260| | |
+------------------+----------+--------------+------------------+
在从服务器上执行
先得到当前主服务器的二进制文件名和偏移量,执行命令使从服务器与主服务器同步
mysql>select master_pos_wait('mysql-bin.0000011','260');
+--------------------------------------------------+
| master_pos_wait('mysql-bin.0000011','260') |
+--------------------------------------------------+
| 0 |
+--------------------------------------------------+
1 row in set (0.01 sec)
+--------------------------------------------------+
| master_pos_wait('mysql-bin.0000011','260') |
+--------------------------------------------------+
| 0 |
+--------------------------------------------------+
1 row in set (0.01 sec)
同步完成后,在主服务器上执行解锁
mysql>unlock tables;
切换主从服务器
当主服务器出现故障时,可将从服务器当主服务器来使用.步骤如下:
1、保证所有从数据库都已经执行了relay log中的全部更新,在从服务器中执行
stop slave io_thread,用show processlist检查,查看状态是否是has read all relay log,表示更新完成.
mysql>stop slave io_thread;
query ok,0 affected (0.00 sec)
mysql>show processlist\g;
query ok,0 affected (0.00 sec)
mysql>show processlist\g;
*************************** 2. row ***************************
id: 2
user: system user
host:
db: null
command: connect
time: 4757
state: has read all relay log; waiting for the slave i/o thread to update it
info: null
id: 2
user: system user
host:
db: null
command: connect
time: 4757
state: has read all relay log; waiting for the slave i/o thread to update it
info: null
2、在从服务器上执行stop slave,reset master命令,重置成主数据库
mysql>stop slave;
query ok,0 affected (0.00 sec)
mysql>reset master;
query ok,0 affected (0.00 sec)
query ok,0 affected (0.00 sec)
mysql>reset master;
query ok,0 affected (0.00 sec)
3、删除新的主服务器数据库目录中的master.info和relay-log.info文件,否则下次重启时还会按照从服务器来启动.