《mycat結(jié)合MySQL雙主實(shí)現(xiàn)讀寫分離》要點(diǎn)：
本文介紹了mycat結(jié)合MySQL雙主實(shí)現(xiàn)讀寫分離，希望對(duì)您有用。如果有疑問，可以聯(lián)系我們。

作者介紹

牛恒博,一線運(yùn)維人,擅長為中小企業(yè)快速實(shí)現(xiàn)運(yùn)維從無到有,再到自動(dòng)化.現(xiàn)就職于某醫(yī)療大數(shù)據(jù)公司.

服務(wù)器拓?fù)?/h1>

服務(wù)器架構(gòu)

安裝MySQL

創(chuàng)建mysql用戶

groupadd mysql
useradd -r -g mysql -s /bin/false mysql

安裝MySQL

yum install -y libaio
cd /usr/local/src/
wget http://mirrors.sohu.com/mysql/MySQL-5.7/mysql-5.7.17-linux-glibc2.5-x86_64.tar.gz
tar -zxf mysql-5.7.17-linux-glibc2.5-x86_64.tar.gz 
cp -rf mysql-5.7.17-linux-glibc2.5-x86_64 /data/app/mysql-3306
cp -rf mysql-5.7.17-linux-glibc2.5-x86_64 /data/app/mysql-3307
chown -R mysql:mysql /data/app/mysql-3306
chown -R mysql:mysql /data/app/mysql-3307
/data/app/mysql-3306/bin/mysqld --initialize-insecure --user=mysql --basedir=/data/app/mysql-3306 --datadir=/data/app/mysql-3306/data
/data/app/mysql-3307/bin/mysqld --initialize-insecure --user=mysql --basedir=/data/app/mysql-3307 --datadir=/data/app/mysql-3307/data

修改my.cnf

需要修改的參數(shù)：?

• server-id：保證每個(gè)配置文件唯一
• 兩臺(tái)master的自增長ID必須不同

linux-node2

master

cat > /data/app/mysql-3306/my.cnf<<EOF
[client]
port = 3306
socket = /data/app/mysql-3306/mysql.sock
[mysqld]

port = 3306
user = mysql
server-id = 1
bind-address = 0.0.0.0
basedir = /data/app/mysql-3306
datadir = /data/app/mysql-3306/data
socket = /data/app/mysql-3306/mysql.sock
pid-file = /data/app/mysql-3306/mysql.pid
log-error = /data/app/mysql-3306/mysqld.log

skip-name-resolve
log_bin = mysql-bin
log-slave-updates
auto-increment-increment = 2 
auto-increment-offset = 1

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
EOF
chown mysql.mysql /data/app/mysql-3306/my.cnf

slave

cat > /data/app/mysql-3307/my.cnf<<EOF
[client]
port = 3307
socket = /data/app/mysql-3307/mysql.sock
[mysqld]

port = 3307
user = mysql
server-id = 11
bind-address = 0.0.0.0
basedir = /data/app/mysql-3307
datadir = /data/app/mysql-3307/data
socket = /data/app/mysql-3307/mysql.sock
pid-file = /data/app/mysql-3307/mysql.pid
log-error = /data/app/mysql-3307/mysqld.log

skip-name-resolve
log_bin = mysql-bin


sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
EOF
chown mysql.mysql /data/app/mysql-3307/my.cnf

linux-node3

master

cat > /data/app/mysql-3306/my.cnf<<EOF
[client]
port = 3306
socket = /data/app/mysql-3306/mysql.sock
[mysqld]

port = 3306
user = mysql
server-id = 2
bind-address = 0.0.0.0
basedir = /data/app/mysql-3306
datadir = /data/app/mysql-3306/data
socket = /data/app/mysql-3306/mysql.sock
pid-file = /data/app/mysql-3306/mysql.pid
log-error = /data/app/mysql-3306/mysqld.log

skip-name-resolve
log_bin = mysql-bin
log-slave-updates
auto-increment-increment = 2 
auto-increment-offset = 2

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
EOF
chown mysql.mysql /data/app/mysql-3306/my.cnf

slave

cat > /data/app/mysql-3307/my.cnf<<EOF
[client]
port = 3307
socket = /data/app/mysql-3307/mysql.sock
[mysqld]

port = 3307
user = mysql
server-id = 22
bind-address = 0.0.0.0
basedir = /data/app/mysql-3307
datadir = /data/app/mysql-3307/data
socket = /data/app/mysql-3307/mysql.sock
pid-file = /data/app/mysql-3307/mysql.pid
log-error = /data/app/mysql-3307/mysqld.log

skip-name-resolve
log_bin = mysql-bin


sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
EOF
chown mysql.mysql /data/app/mysql-3307/my.cnf

啟動(dòng)MySQL

啟動(dòng)服務(wù)

linux-node2和linux-node3都執(zhí)行如下命令

touch /data/app/mysql-3306/mysqld.log && chown mysql.mysql /data/app/mysql-3306/mysqld.log
sed -i 's#/usr/local/mysql#/data/app/mysql-3306#g' /data/app/mysql-3306/bin/mysqld_safe 
/data/app/mysql-3306/bin/mysqld_safe --defaults-file=/data/app/mysql-3306/my.cnf --basedir=/data/app/mysql-3306 --datadir=/data/app/mysql-3306/data --user=mysql &


touch /data/app/mysql-3307/mysqld.log && chown mysql.mysql /data/app/mysql-3307/mysqld.log
sed -i 's#/usr/local/mysql#/data/app/mysql-3307#g' /data/app/mysql-3307/bin/mysqld_safe 
/data/app/mysql-3307/bin/mysqld_safe --defaults-file=/data/app/mysql-3307/my.cnf --basedir=/data/app/mysql-3307 --datadir=/data/app/mysql-3307/data --user=mysql &

檢查端口

ss -lntup |egrep '3306|3307'
tcp ? ?LISTEN ? ? 0 ? ? ?80 ? ? ? ? ? ? ? ? ? ? *:3306 ? ? ? ? ? ? ? ? ?*:* ? ? ?users:(("mysqld",19973,22))
tcp ? ?LISTEN ? ? 0 ? ? ?80 ? ? ? ? ? ? ? ? ? ? *:3307 ? ? ? ? ? ? ? ? ?*:* ? ? ?users:(("mysqld",20537,22))

配置雙主

配置主從

linux-node2

master

cd /data/app/mysql-3306/
./bin/mysql -uroot -p -S mysql.sock -P 3306
mysql> CREATE USER 'repl'@'192.%' IDENTIFIED BY 'mysql';
Query OK, 0 rows affected (0.05 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.%';
Query OK, 0 rows affected (0.00 sec)

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File ? ? ? ? ? ? | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | ? ? ?613 | ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

slave

cd /data/app/mysql-3307/
./bin/mysql -uroot -p -S mysql.sock -P 3307
mysql> CHANGE MASTER TO MASTER_HOST='192.168.56.12', 
 ? ?-> ? ? ? ? ? ? ? ? ?MASTER_PORT=3306, 
 ? ?-> ? ? ? ? ? ? ? ? ?MASTER_USER='repl', 
 ? ?-> ? ? ? ? ? ? ? ? ?MASTER_PASSWORD='mysql', 
 ? ?-> ? ? ? ? ? ? ? ? ?MASTER_LOG_FILE='mysql-bin.000001', 
 ? ?-> ? ? ? ? ? ? ? ? ?MASTER_LOG_POS=613;
Query OK, 0 rows affected, 2 warnings (0.04 sec)

mysql> start slave;
Query OK, 0 rows affected (0.02 sec)
mysql> show slave status\G
*************************** 1. row ***************************
 ? ? ? ? ? ? ? Slave_IO_State: Waiting for master to send event
 ? ? ? ? ? ? ? ? ?Master_Host: 192.168.56.12
 ? ? ? ? ? ? ? ? ?Master_User: repl
 ? ? ? ? ? ? ? ? ?Master_Port: 3306
 ? ? ? ? ? ? ? ?Connect_Retry: 60
 ? ? ? ? ? ? ?Master_Log_File: mysql-bin.000001
 ? ? ? ? ?Read_Master_Log_Pos: 613
 ? ? ? ? ? ? ? Relay_Log_File: linux-node2-relay-bin.000002
 ? ? ? ? ? ? ? ?Relay_Log_Pos: 320
 ? ? ? ?Relay_Master_Log_File: mysql-bin.000001
 ? ? ? ? ? ? Slave_IO_Running: Yes
 ? ? ? ? ? ?Slave_SQL_Running: Yes

linux-node3

master

cd /data/app/mysql-3306/
./bin/mysql -uroot -p -S mysql.sock -P 3306
mysql> CREATE USER 'repl'@'192.%' IDENTIFIED BY 'mysql';
Query OK, 0 rows affected (0.05 sec)

mysql> GRANT REPLICATION SLAVE ON *.* TO 'repl'@'192.%';
Query OK, 0 rows affected (0.00 sec)

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File ? ? ? ? ? ? | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | ? ? ?613 | ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

slave

cd /data/app/mysql-3307/
./bin/mysql -uroot -p -S mysql.sock -P 3307
mysql> 
CHANGE MASTER TO MASTER_HOST='192.168.56.13', 
 ? ? ? ? ? ? ? ? MASTER_PORT=3306, 
 ? ? ? ? ? ? ? ? MASTER_USER='repl', 
 ? ? ? ? ? ? ? ? MASTER_PASSWORD='mysql', 
 ? ? ? ? ? ? ? ? MASTER_LOG_FILE='mysql-bin.000001', 
 ? ? ? ? ? ? ? ? MASTER_LOG_POS=613;
Query OK, 0 rows affected, 2 warnings (0.04 sec)

mysql> start slave;
Query OK, 0 rows affected (0.02 sec)
mysql> show slave status\G
*************************** 1. row ***************************
 ? ? ? ? ? ? ? Slave_IO_State: Waiting for master to send event
 ? ? ? ? ? ? ? ? ?Master_Host: 192.168.56.13
 ? ? ? ? ? ? ? ? ?Master_User: repl
 ? ? ? ? ? ? ? ? ?Master_Port: 3306
 ? ? ? ? ? ? ? ?Connect_Retry: 60
 ? ? ? ? ? ? ?Master_Log_File: mysql-bin.000001
 ? ? ? ? ?Read_Master_Log_Pos: 613
 ? ? ? ? ? ? ? Relay_Log_File: linux-node2-relay-bin.000002
 ? ? ? ? ? ? ? ?Relay_Log_Pos: 320
 ? ? ? ?Relay_Master_Log_File: mysql-bin.000001
 ? ? ? ? ? ? Slave_IO_Running: Yes
 ? ? ? ? ? ?Slave_SQL_Running: Yes

配置雙主

master的binlog位置

linux-node2 master端

d /data/app/mysql-3306/
./bin/mysql -uroot -p -S mysql.sock -P 3306
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File ? ? ? ? ? ? | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | ? ? ?613 | ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

linux-node3 master端

cd /data/app/mysql-3306/
./bin/mysql -uroot -p -S mysql.sock -P 3306
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File ? ? ? ? ? ? | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | ? ? ?613 | ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ?| ? ? ? ? ? ? ? ? ? |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

linux-node2 master配置跟linux-node3 master同步

mysql> CHANGE MASTER TO MASTER_HOST='192.168.56.13', 
 ? ? ? ? ? ? ? ? MASTER_PORT=3306, 
 ? ? ? ? ? ? ? ? MASTER_USER='repl', 
 ? ? ? ? ? ? ? ? MASTER_PASSWORD='mysql', 
 ? ? ? ? ? ? ? ? MASTER_LOG_FILE='mysql-bin.000001', 
 ? ? ? ? ? ? ? ? MASTER_LOG_POS=613;
mysql> start slave;
Query OK, 0 rows affected (0.03 sec)

mysql> show slave status\G
*************************** 1. row ***************************
 ? ? ? ? ? ? ? Slave_IO_State: Waiting for master to send event
 ? ? ? ? ? ? ? ? ?Master_Host: 192.168.56.13
 ? ? ? ? ? ? ? ? ?Master_User: repl
 ? ? ? ? ? ? ? ? ?Master_Port: 3306
 ? ? ? ? ? ? ? ?Connect_Retry: 60
 ? ? ? ? ? ? ?Master_Log_File: mysql-bin.000001
 ? ? ? ? ?Read_Master_Log_Pos: 613
 ? ? ? ? ? ? ? Relay_Log_File: linux-node2-relay-bin.000002
 ? ? ? ? ? ? ? ?Relay_Log_Pos: 320
 ? ? ? ?Relay_Master_Log_File: mysql-bin.000001
 ? ? ? ? ? ? Slave_IO_Running: Yes
 ? ? ? ? ? ?Slave_SQL_Running: Yes ? ? ? ? 

linux-node3 master配置跟linux-node2 master同步

mysql> CHANGE MASTER TO MASTER_HOST='192.168.56.12', 
 ? ? ? ? ? ? ? ? MASTER_PORT=3306, 
 ? ? ? ? ? ? ? ? MASTER_USER='repl', 
 ? ? ? ? ? ? ? ? MASTER_PASSWORD='mysql', 
 ? ? ? ? ? ? ? ? MASTER_LOG_FILE='mysql-bin.000001', 
 ? ? ? ? ? ? ? ? MASTER_LOG_POS=613;
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> 
mysql> show slave status\G
*************************** 1. row ***************************
 ? ? ? ? ? ? ? Slave_IO_State: Waiting for master to send event
 ? ? ? ? ? ? ? ? ?Master_Host: 192.168.56.12
 ? ? ? ? ? ? ? ? ?Master_User: repl
 ? ? ? ? ? ? ? ? ?Master_Port: 3306
 ? ? ? ? ? ? ? ?Connect_Retry: 60
 ? ? ? ? ? ? ?Master_Log_File: mysql-bin.000001
 ? ? ? ? ?Read_Master_Log_Pos: 613
 ? ? ? ? ? ? ? Relay_Log_File: linux-node3-relay-bin.000002
 ? ? ? ? ? ? ? ?Relay_Log_Pos: 320
 ? ? ? ?Relay_Master_Log_File: mysql-bin.000001
 ? ? ? ? ? ? Slave_IO_Running: Yes
 ? ? ? ? ? ?Slave_SQL_Running: Yes

驗(yàn)證

從linux-node2上驗(yàn)證

在linux-node2 master上創(chuàng)建數(shù)據(jù)

mysql> create database test;
Query OK, 1 row affected (0.01 sec)

mysql> use test;
Database changed

mysql> create table temp(id int,name varchar(64));
Query OK, 0 rows affected (0.11 sec)

mysql> insert into temp values(1,'aaa');
Query OK, 1 row affected (0.28 sec)

mysql> CREATE TABLE temp2(id INT PRIMARY KEY ?NOT NULL AUTO_INCREMENT ,nname VARCHAR(64));
Query OK, 0 rows affected (0.01 sec)

mysql> insert into temp2(nname) values('bbb');
Query OK, 1 row affected (0.01 sec)

mysql> select * from test.temp;
+------+------+
| id ? | name |
+------+------+
| ? ?1 | aaa ?|
+------+------+
1 row in set (0.01 sec)

在linux-node2 slave上查看數(shù)據(jù)

mysql> select * from test.temp;
+------+------+
| id ? | name |
+------+------+
| ? ?1 | aaa ?|
+------+------+
1 row in set (0.00 sec)

在linux-node3 master上查看數(shù)據(jù)

mysql> select * from test.temp;
+------+------+
| id ? | name |
+------+------+
| ? ?1 | aaa ?|
+------+------+
1 row in set (0.00 sec)

在linux-node3 slave上查看數(shù)據(jù)

mysql> select * from test.temp;
+------+------+
| id ? | name |
+------+------+
| ? ?1 | aaa ?|
+------+------+
1 row in set (0.00 sec)

從linux-node3上驗(yàn)證

在linux-node3 master上創(chuàng)建數(shù)據(jù)

mysql> use test;

mysql> insert into temp2(nname) values('ddd');
Query OK, 1 row affected (0.02 sec)
mysql> ?insert into temp2(nname) values('fff');
Query OK, 1 row affected (0.00 sec)

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
+----+-------+

在linux-node3 slave上查看數(shù)據(jù)

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
+----+-------+
3 rows in set (0.00 sec)

在linux-node2 master上查看數(shù)據(jù)

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
+----+-------+
3 rows in set (0.00 sec)

在linux-node2 slave上查看數(shù)據(jù)

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
+----+-------+
3 rows in set (0.00 sec)

結(jié)論

• 在任意一個(gè)master端更新數(shù)據(jù),其他任意端都可以更新數(shù)據(jù)
• 兩臺(tái)服務(wù)器配置了間隔自增長,數(shù)據(jù)不同沖突

linux-node1上安裝mycat

安裝mycat

cd /usr/local/src
wget http://dl.mycat.io/1.6-RELEASE/Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz
tar -zxf Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz 
mv mycat /data/app/mycat-1.6
ln -s /data/app/mycat-1.6 /data/app/mycat

修改schema.xml

• balance="1"
  全部的readHost與stand by writeHost參與select語句的負(fù)載均衡
• writeType="0"
  所有寫操作發(fā)送到配置的第一個(gè)writeHost,第一個(gè)掛了切到還生存的第二個(gè) writeHost,重新啟動(dòng)后以切換后的為準(zhǔn),切換記錄在配置文件中:dnindex.properties
• switchType="1"
  默認(rèn)值為1,自動(dòng)切換

cd /data/app/mycat
cp conf/schema.xml conf/schema.xml.bak
cat > conf/schema.xml <<EOF
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="true" sqlMaxLimit="100" dataNode="dn1"></schema>
 ? ?<dataNode name="dn1" dataHost="node1" database="test" />
 ? ?<dataHost name="node1" maxCon="10" minCon="5" balance="1" writeType="0" dbType="mysql" dbDriver="native" switchType="1">
 ? ? ? ?<heartbeat>select user()</heartbeat>
 ? ? ? ?<writeHost host="master1" url="192.168.56.12:3306" user="root" password="mysql">
 ? ? ? ? ? ?<readHost host="slave2" url="192.168.56.13:3307" user="root" password="mysql" />
 ? ? ? ?</writeHost>
 ? ? ? ?<writeHost host="master2" url="192.168.56.13:3306" user="root" password="mysql">
 ? ? ? ? ? ?<readHost host="slave2" url="192.168.56.13:3307" user="root" password="mysql" />
 ? ? ? ?</writeHost>
 ? ?</dataHost>
</mycat:schema>
EOF

啟動(dòng)mycat

./bin/mycat start 
ss -lntup |egrep ?'(8066|9066)' ?
tcp ? ?LISTEN ? ? 0 ? ? ?100 ? ? ? ? ? ? ? ? ? :::8066 ? ? ? ? ? ? ? ? :::* ? ? ?users:(("java",16546,79))
tcp ? ?LISTEN ? ? 0 ? ? ?100 ? ? ? ? ? ? ? ? ? :::9066 ? ? ? ? ? ? ? ? :::* ? ? ?users:(("java",16546,75))

驗(yàn)證mycat服務(wù)是否正常

在linux-node2-master端配置mycat連接賬號(hào)

mysql> GRANT ALL PRIVILEGES ON *.* TO root@'192.%' IDENTIFIED BY 'mysql'; 
Query OK, 0 rows affected, 1 warning (0.07 sec

在mycat服務(wù)器上安裝mysql服務(wù),但是不啟動(dòng)

步驟省略,詳細(xì)內(nèi)容可以參考上面的MySQL安裝

使用mysql的客戶端連接mycat

cd /data/app/mysql/
./bin/mysql -uroot -p -P 8066 -h 192.168.56.11 ##連接mycat,初始密碼123456
mysql> show databases;
+----------+
| DATABASE |
+----------+
| TESTDB ? |
+----------+
1 row in set (0.00 sec)

mysql> use TESTDB;

mysql> insert into temp2(nname) values('eee');
Query OK, 1 row affected (0.09 sec)
mysql> insert into temp2(nname) values('ggg');
Query OK, 1 row affected (0.01 sec)

linux-node3 slave端查看數(shù)據(jù)是否同步

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
| ?5 | eee ? |
| ?7 | ggg ? |
+----+-------+
5 rows in set (0.00 sec)

結(jié)果發(fā)現(xiàn)數(shù)據(jù)寫入到了linux-node2 slave端

測(cè)試

服務(wù)自動(dòng)遷移

關(guān)閉linux-node2 master的MySQL服務(wù)

mysql> shutdown;
Query OK, 0 rows affected (0.01 sec)

shell > ss -lntup |grep 3306

mycat端插入新的數(shù)據(jù)查看數(shù)據(jù)是否同步

mysql> insert into temp2(nname) values('mmmm');
Query OK, 1 row affected (0.07 sec)

mysql> insert into temp2(nname) values('nnnn');
Query OK, 1 row affected (0.01 sec)

linux-node3 slave端查看數(shù)據(jù)是否同步

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
| ?5 | eee ? |
| ?7 | ggg ? |
| ?8 | mmmm ?|
| 10 | nnnn ?|
+----+-------+
7 rows in set (0.00 sec)

linux-node2 slave端查看數(shù)據(jù)是否同步

mysql> select * from test.temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
| ?5 | eee ? |
| ?7 | ggg ? |
+----+-------+
5 rows in set (0.00 sec)
 發(fā)現(xiàn)因?yàn)閘inux-node2的master端已經(jīng)掛了,數(shù)據(jù)不能同步了

數(shù)據(jù)訪問是否正常

登錄到mycat服務(wù)器上執(zhí)行如下命令：

mysql> select * from temp2;
+----+-------+
| id | nname |
+----+-------+
| ?1 | bbb ? |
| ?2 | ddd ? |
| ?4 | fff ? |
| ?5 | eee ? |
| ?7 | ggg ? |
| ?8 | mmmm ?|
| 10 | nnnn ?|
+----+-------+
7 rows in set (0.00 sec) 
執(zhí)行多次發(fā)現(xiàn)結(jié)果一樣,說明在一臺(tái)master端掛掉的情況下,其連接的slave端也被剔除,因此數(shù)據(jù)完整性可以保證

故障匯總

第一次配置的時(shí)候maser端沒有配置log-slave-updates,導(dǎo)致node3-slave上沒有node2-master端的數(shù)據(jù).
解釋：
從庫開啟log-bin參數(shù),如果直接往從庫寫數(shù)據(jù),是可以記錄log-bin日志的,但是從庫通過I0線程讀取主庫二進(jìn)制日志文件,然后通過SQL線程寫入的數(shù)據(jù),是不會(huì)記錄binlog日志的.也就是說從庫從主庫上復(fù)制的數(shù)據(jù),是不寫入從庫的binlog日志的.所以從庫做為其他從庫的主庫時(shí)需要在配置文件中添加log-slave-updates參數(shù).

解決辦法：

[mysqld]
log-slave-updates

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