MySQL數據庫的主從配置(多主對一從)

一、實驗環境部署

主服務器 192.168.18.42 端口3306  ==》 從服務器 192.168.18.44 端口 3306    
主服務器 192.168.18.43 端口3306  ==》 從服務器 192.168.18.44 端口 3307

##數據庫，已經安裝mysql服務，安裝部分略。從服務器上的多個mysql實例，請看另一篇帖子《用mysql_multi 實現一臺機器跑多臺mysql 》

二、部署服務器

1.在兩臺主服務器上賦予從機權限，有多臺叢機，就執行多次（我們這里兩臺主庫使用統一帳號密碼）。

mysql> grant replication slave on *.* to 'backup'@'192.168.18.44' identified by '123456';
Query OK, 0 rows affected (0.00 sec)

2.在主服務器上配置my.cnf

vi /etc/my.cnf

server-id = 1
log-bin = mysql-bin  #保證binlog可讀
read-only = 0  #主機，讀寫都可以
#binlog-do-db = test   #需要備份數據，多個寫多行，不寫全部都備份
binlog-ignore-db = mysql #不需要備份的數據庫，多個寫多行

編輯后重啟數據庫 # service mysqld restart

3.配置從庫服務器的my.cnf

vi /etc/my.cnf

[mysqld_multi]
mysqld = /mysql/bin/mysqld_safe
mysqladmin = /mysql/bin/mysqladmin

[mysqld1]
port    = 3306
socket  = /tmp/mysql3306.sock
pid-file = /data/mysql/data1/mysql3306.pid
datadir = /data/mysql/data1
skip-name-resolve
log-bin = mysql-bin-3306
log_slave_updates
expire_logs_days = 7
log-error = /data/mysql/data1/mysql3306.err
log_slow_queries = mysql3306-slow.log
long_query_time = 3
query_cache_size = 64M
query_cache_limit = 2M
slave-net-timeout = 10
server-id = 2                     #server id 不要與主庫的重復
master-host = 192.168.18.42        #對應主庫的 ip地址
master-user = backup               # slave 帳號
master-password = 123456           # 密碼
master-port = 3306                 #主庫端口
replicate-ignore-db=mysql           #跳過不備份的庫
master-info-file = master.1842.info
master-connect-retry = 10
relay-log = relay-bin-1842          #中繼日志
relay-log-index = relay-bin-1842
relay-log-info-file = relay-log-1842.info
default-character-set=gbk
innodb_data_home_dir = /data/mysql/data1
innodb_data_file_path = ibdata1:50M:autoextend
innodb_log_group_home_dir = /data/mysql/data1
innodb_buffer_pool_size = 3072M
innodb_file_per_table
innodb_open_files = 800
#innodb_flush_method = O_DIRECT
innodb_flush_method = O_DSYNC
skip-locking
key_buffer = 32M
max_allowed_packet = 16M
table_cache = 1024
sort_buffer_size = 8M
net_buffer_length = 8M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 32M
max_connections = 100
read_only
wait_timeout=288000
interactive_timeout=288000
log-bin-trust-function-creators=1
replicate-ignore-db = test
replicate-ignore-table = mysql.columns_priv
replicate-ignore-table = mysql.host
replicate-ignore-table = mysql.db
replicate-ignore-table = mysql.procs_priv
replicate-ignore-table = mysql.tables_priv
replicate-ignore-table = mysql.user



[mysqld2]
port    = 3307
socket  = /tmp/mysql3307.sock
pid-file = /data/mysql/data2/mysql3307.pid
datadir = /data/mysql/data2
skip-name-resolve
log-bin = mysql-bin-3307
log_slave_updates
expire_logs_days = 7
log-error = /data/mysql/data1/mysql3307.err
log_slow_queries = mysql3307-slow.log
long_query_time = 3
query_cache_size = 64M
query_cache_limit = 2M
slave-net-timeout = 10
server-id = 2                     #server id 不要與主庫的重復
master-host = 192.168.18.43        #對應主庫的 ip地址
master-user = backup               # slave 帳號
master-password = 123456           # 密碼
master-port = 3306                 #主庫端口
replicate-ignore-db=mysql           #跳過不備份的庫
master-info-file = master.1843.info
master-connect-retry = 10
relay-log = relay-bin-1843
relay-log-index = relay-bin-1843
relay-log-info-file = relay-log-1843.info
default-character-set=gbk
innodb_data_home_dir = /data/mysql/data2
innodb_data_file_path = ibdata1:50M:autoextend
innodb_log_group_home_dir = /data/mysql/data2
innodb_buffer_pool_size = 3072M
innodb_file_per_table
innodb_open_files = 800
#innodb_flush_method = O_DIRECT
innodb_flush_method = O_DSYNC
skip-locking
key_buffer = 32M
max_allowed_packet = 16M
table_cache = 1024
sort_buffer_size = 8M
net_buffer_length = 8M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 32M
max_connections = 100
read_only
wait_timeout=288000
interactive_timeout=288000
log-bin-trust-function-creators=1
replicate-ignore-db = test
replicate-ignore-table = mysql.columns_priv
replicate-ignore-table = mysql.host
replicate-ignore-table = mysql.db
replicate-ignore-table = mysql.procs_priv
replicate-ignore-table = mysql.tables_priv
replicate-ignore-table = mysql.user

# 因為圖方便就把參數全部抓出來了 對主從有用的也就標注的幾個

4.配置完成后重啟大從服務器
[root@localhost data1]# mysqld_multi --config-file=/etc/my.cnf --user=root --password=123456 report 1,2
Reporting MySQL servers
MySQL server from group: mysqld1 is running
MySQL server from group: mysqld2 is running

5.在從庫上進行chang master ；
1）.在date1上
mysql -uroot -p -S /tmp/mysql3306.sock

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO
    -> MASTER_HOST='192.168.18.43',
    -> MASTER_PORT=3306,
    -> MASTER_USER='backup',
    -> MASTER_PASSWORD='123456'
Query OK, 0 rows affected (0.05 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

2）。在date2上

mysql -uroot -p -S /tmp/mysql3307.sock

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql> CHANGE MASTER TO
    -> MASTER_HOST='192.168.18.42',
    -> MASTER_PORT=3306,
    -> MASTER_USER='backup',
    -> MASTER_PASSWORD='123456'
Query OK, 0 rows affected (0.05 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)


三、驗證：
1.在大從服務器上

  show slave status\G; 

  Slave_IO_Running: Yes
  Slave_SQL_Running: Yes

2.在主庫創建數據庫（18.43上）

mysql> create database haifengtest;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema | 
| haifengtest        | 
| mysql              | 
| test               | 
+--------------------+
4 rows in set (0.00 sec)

從庫查看 (mysql3307.sock上）

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema | 
| haifengtest        | 
| mysql              | 
| test               | 
+--------------------+
4 rows in set (0.00 sec)

四、一種常見的問題。

在show slave status\G；時發現下面的問題，（因為我事先在從上創建了該庫）

  Relay_Master_Log_File: mysql-bin.000005
           Slave_IO_Running: Yes
          Slave_SQL_Running: No
            Replicate_Do_DB: 
        Replicate_Ignore_DB: mysql
         Replicate_Do_Table: 
     Replicate_Ignore_Table: 
    Replicate_Wild_Do_Table: 
Replicate_Wild_Ignore_Table: 
                 Last_Errno: 1007
                 Last_Error: Error 'Can't create database 'haifengtest'; database exists' on query. Default database: 'haifengtest'. Query: 'create database haifengtest'

如果Replication在Slave上出現上面錯誤而停止，一般都期望Slave能忽略這個錯誤，繼續進行同步，而不是重新啟動Slave。

　這時可以使用 SQL_SLAVE_SKIP_COUNTER

mysql> SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

在驗證一次

  show slave status\G; 

  Slave_IO_Running: Yes
  Slave_SQL_Running: Yes