一、什么是MySQL多實例？
MySQL多實例簡單的說就是在一臺服務器上安裝一套MySQL程序，通過不同的端口對外提供訪問，多實例不僅節(jié)省物理主機成本，還有效提升了單臺物理主機的CPU、磁盤I/O使用效率，而且還可以在多實例之間做部署數(shù)據(jù)庫HA方案。
二、如何配置MySQL多實例？
配置mysql多實例有兩種方式
1、根據(jù)官方提供的是通過mysqld_multi使用單獨的配置文件來實現(xiàn)多實例，這種方式定制每個實例的配置不太方面，優(yōu)點是管理起來很方便，集中管理。
2、使用多個配置文件和啟動文件，配置文件之間的區(qū)別：server-id、socket文件的位置、配置路徑和數(shù)據(jù)存放位置不同。初始化的時候只用不同的配置文件進行初始化數(shù)據(jù)庫，啟動時使用不同的啟動文件來啟動，這種方法邏輯和配置簡單，但是不方便管理。
下面我們以第二種多實例的方法進行配置
三、多實例配置
MySQL安裝的是mysql5.5.52版本，安裝方法請看MySQL5.5.52編譯安裝
1、停止單實例mysql數(shù)據(jù)庫
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[root@db01 ~]# /etc/init.d/mysqld stop Shutting down MySQL. SUCCESS!
2、禁止開機自啟動
[root@db01 ~]# chkconfig mysqld off [root@db01 ~]# chkconfig --list mysqld mysqld 0:關閉 1:關閉 2:關閉 3:關閉 4:關閉 5:關閉6:關閉
3、創(chuàng)建多實例根目錄/data/目錄
重慶分公司
重慶分公司
[root@db01 ~]# mkdir -p /data/{3306,3307}/data需要特別說明一下，在多實例啟動文件中，啟動MySQL不同勢力服務所需要執(zhí)行的命令實質(zhì)是有區(qū)別的，例如，啟動3306實例命令如下
mysql_safe --defaults-file=/data/3306/mysql &>/dev/null
啟動3307實例的命令如下：
mysql_safe --defaults-file=/data/3307/mysql &>/dev/null
下面看看多實例啟動文件中，停止MySQL不同實例服務的實質(zhì)命令
停止3306實例的命令如下：
mysqladmin -uroot -p123456 -S /data/3306/mysql.sock shutdown
停止3307實例的命令如下：
mysqladmin -uroot -p123456 -S /data/3307/mysql.sock shutdown
4、創(chuàng)建MySQL多實例的配置文件和啟動文件
1）3306mysql實例配置文件
[root@db01 ~]# vim /data/3306/my.cnf [client] port = 3306 socket = /data/3306/mysql.sock [mysql] no-auto-rehash [mysqld] user = mysql port = 3306 socket = /data/3306/mysql.sock basedir = /application/mysql datadir = /data/3306/data open_files_limit = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_cache = 614 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k #default_table_type = InnoDB thread_stack = 192K #transaction_isolation = READ-COMMITTED tmp_table_size = 2M max_heap_table_size = 2M long_query_time = 1 #log_long_format #log-error = /data/3306/error.log #log-slow-queries = /data/3306/slow.log pid-file = /data/3306/mysql.pid log-bin = /data/3306/mysql-bin relay-log = /data/3306/relay-bin relay-log-info-file = /data/3306/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M #myisam_sort_buffer_size = 1M #myisam_max_sort_file_size = 10G #myisam_max_extra_sort_file_size = 10G #myisam_repair_threads = 1 #myisam_recover lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 1 innodb_additional_mem_pool_size = 4M innodb_buffer_pool_size = 32M innodb_data_file_path = ibdata1:128M:autoextend innodb_file_io_threads = 4 innodb_thread_concurrency = 8 innodb_flush_log_at_trx_commit = 2 innodb_log_buffer_size = 2M innodb_log_file_size = 4M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 innodb_file_per_table = 0 [mysqldump] quick max_allowed_packet = 2M [mysqld_safe] log-error=/data/3306/mysql_3306.err pid-file=/data/3306/mysqld.pid
2）3307mysql實例配置文件
[root@db01 ~]# cp /data/3306/my.cnf /data/3307/my.cnf [root@db01 ~]# sed -i 's#3306#3307#g' /data/3307/my.cnf [root@db01 ~]# sed -n /server-id/p /data/3307/my.cnf server-id = 1 [root@db01 ~]# sed -i 's#server-id = 1#server-id = 2#g' /data/3307/my.cnf [root@db01 ~]# cat /data/3307/my.cnf [client] port = 3307 socket = /data/3307/mysql.sock [mysql] no-auto-rehash [mysqld] user = mysql port = 3307 socket = /data/3307/mysql.sock basedir = /application/mysql datadir = /data/3307/data open_files_limit = 1024 back_log = 600 max_connections = 800 max_connect_errors = 3000 table_cache = 614 external-locking = FALSE max_allowed_packet =8M sort_buffer_size = 1M join_buffer_size = 1M thread_cache_size = 100 thread_concurrency = 2 query_cache_size = 2M query_cache_limit = 1M query_cache_min_res_unit = 2k #default_table_type = InnoDB thread_stack = 192K #transaction_isolation = READ-COMMITTED tmp_table_size = 2M max_heap_table_size = 2M long_query_time = 1 #log_long_format #log-error = /data/3307/error.log #log-slow-queries = /data/3307/slow.log pid-file = /data/3307/mysql.pid log-bin = /data/3307/mysql-bin relay-log = /data/3307/relay-bin relay-log-info-file = /data/3307/relay-log.info binlog_cache_size = 1M max_binlog_cache_size = 1M max_binlog_size = 2M expire_logs_days = 7 key_buffer_size = 16M read_buffer_size = 1M read_rnd_buffer_size = 1M bulk_insert_buffer_size = 1M #myisam_sort_buffer_size = 1M #myisam_max_sort_file_size = 10G #myisam_max_extra_sort_file_size = 10G #myisam_repair_threads = 1 #myisam_recover lower_case_table_names = 1 skip-name-resolve slave-skip-errors = 1032,1062 replicate-ignore-db=mysql server-id = 2 innodb_additional_mem_pool_size = 4M innodb_buffer_pool_size = 32M innodb_data_file_path = ibdata1:128M:autoextend innodb_file_io_threads = 4 innodb_thread_concurrency = 8 innodb_flush_log_at_trx_commit = 2 innodb_log_buffer_size = 2M innodb_log_file_size = 4M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 innodb_file_per_table = 0 [mysqldump] quick max_allowed_packet = 2M [mysqld_safe] log-error=/data/3307/mysql_3307.err pid-file=/data/3307/mysqld.pid
5、MySQL多實例啟動文件的創(chuàng)建和配置文件創(chuàng)建幾乎一樣，也可以通過vim命令來添加如下：
1）3306mysql實例啟動文件
[root@db01 ~]# vim /data/3306/mysql
#!/bin/bash
################################################
# Filename:mysql
# Description:Start MySQL multi instance script
# Version:1.0
# Date:2016/12/10
# Author:xuanwiei
# Email:1756112532@qq.com
################################################
#init
port=3306
mysql_user="root"
mysql_pwd="123456" #這里將來是要修改為和數(shù)據(jù)庫密碼一致
CmdPath="/application/mysql/bin"
mysql_sock="/data/${port}/mysql.sock"
#startup function
function_start_mysql()
{
if [ ! -e "$mysql_sock" ];then
printf "Starting MySQL...\n"
/bin/sh ${CmdPath}/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &
else
printf "MySQL is running...\n"
exit
fi
}
#stop function
function_stop_mysql()
{
if [ ! -e "$mysql_sock" ];then
printf "MySQL is stopped...\n"
exit
else
printf "Stoping MySQL...\n"
${CmdPath}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S /data/${port}/mysql.sock shutdown
fi
}
#restart function
function_restart_mysql()
{
printf "Restarting MySQL...\n"
function_stop_mysql
sleep 2
function_start_mysql
}
case $1 in
start)
function_start_mysql
;;
stop)
function_stop_mysql
;;
restart)
function_restart_mysql
;;
*)
printf "Usage: /data/${port}/mysql {start|stop|restart}\n"
esac2）3307mysql實例啟動文件
[root@db01 ~]# cp /data/3306/mysql /data/3307/mysql
[root@db01 ~]# sed -i 's#3306#3307#g' /data/3307/mysql
[root@db01 ~]# cat /data/3307/mysql
#!/bin/bash
################################################
# Filename: mysql
# Description: Start MySQL multi instance script
# Version: 1.0
# Date: 2016/12/10
# Author: xuanwiei
# Email: 1756112532@qq.com
################################################
#init
port=3307
mysql_user="root"
mysql_pwd="123456"
CmdPath="/application/mysql/bin"
mysql_sock="/data/${port}/mysql.sock"
#startup function
function_start_mysql()
{
if [ ! -e "$mysql_sock" ];then
printf "Starting MySQL...\n"
/bin/sh ${CmdPath}/mysqld_safe --defaults-file=/data/${port}/my.cnf 2>&1 > /dev/null &
else
printf "MySQL is running...\n"
exit
fi
}
#stop function
function_stop_mysql()
{
if [ ! -e "$mysql_sock" ];then
printf "MySQL is stopped...\n"
exit
else
printf "Stoping MySQL...\n"
${CmdPath}/mysqladmin -u ${mysql_user} -p${mysql_pwd} -S /data/${port}/mysql.sock shutdown
fi
}
#restart function
function_restart_mysql()
{
printf "Restarting MySQL...\n"
function_stop_mysql
sleep 2
function_start_mysql
}
case $1 in
start)
function_start_mysql
;;
stop)
function_stop_mysql
;;
restart)
function_restart_mysql
;;
*)
printf "Usage: /data/${port}/mysql {start|stop|restart}\n"
esac6、配置MySQL多實例的文件權限
（1）通過下面的命令授權mysql用戶和用戶組管理整個多實例的根目錄/data
[root@db01 ~]# chown -R mysql.mysql /data
（2）通過下面的mysql多實例所有啟動文件的mysql可執(zhí)行，設置700權限最佳，注意不要用755權限，因為文件里有數(shù)據(jù)庫管理員密碼，會被讀取到。
[root@db01 scripts]# find /data/ -type f -name "mysql" /data/3306/mysql /data/3307/mysql [root@db01 scripts]# find /data/ -type f -name "mysql"|xargs chmod 700 [root@db01 scripts]# find /data/ -type f -name "mysql"|xargs ls -l -rwx------ 1 root root 1359 12月 10 16:20 /data/3306/mysql -rwx------ 1 root root 1359 12月 10 16:22 /data/3307/mysql
7、初始化MySQL多實例的數(shù)據(jù)庫文件
（1）初始化MySQL數(shù)據(jù)庫
cd /application/mysql/scripts/ <==注意和MySQL5.1的路徑不同，MySQL5.1不在MySQL bin路徑下了
3306實例
/application/mysql/scripts/mysql_install_db \
--basedir=/application/mysql \
--datadir=/data/3306/data \
--user=mysql
3307實例
/application/mysql/scripts/mysql_install_db \
--basedir=/application/mysql \
--datadir=/data/3307/data \
--user=mysql
提示：--basedir=/application/mysql為MySQL的安裝路徑，--datadir為不同的實例數(shù)據(jù)目錄
操作過程：
[root@db01 ~]# cd /application/mysql/scripts/ [root@db01 scripts]# /application/mysql/scripts/mysql_install_db \ > --basedir=/application/mysql \ > --datadir=/data/3306/data \ > --user=mysql WARNING: The host 'db01' could not be looked up with resolveip. This probably means that your libc libraries are not 100 % compatible with this binary MySQL version. The MySQL daemon, mysqld, should work normally with the exception that host name resolving will not work. This means that you should use IP addresses instead of hostnames when specifying MySQL privileges ! Installing MySQL system tables... 161117 14:14:14 [Note] /application/mysql/bin/mysqld (mysqld 5.5.52) starting as process 46676 ... OK Filling help tables... 161117 14:14:15 [Note] /application/mysql/bin/mysqld (mysqld 5.5.52) starting as process 46683 ... OK
如果有兩個ok，就表示初始化成功
其中WARNING: The host 'db01' could not be looked up with resolveip.
原因是因為db01沒有在hosts文件中解析
解決：echo "172.16.1.52 db01" >>/etc/hosts
[root@db01 scripts]# /application/mysql/scripts/mysql_install_db \ > --basedir=/application/mysql \ > --datadir=/data/3307/data \ > --user=mysql Installing MySQL system tables... 161117 14:18:20 [Note] /application/mysql/bin/mysqld (mysqld 5.5.52) starting as process 46733 ... OK Filling help tables... 161117 14:18:21 [Note] /application/mysql/bin/mysqld (mysqld 5.5.52) starting as process 46740 ... OK
如果有兩個ok，就表示初始化成功
這次沒用出現(xiàn)WARNING: The host 'db01' could not be looked up with resolveip.
（2）初始化數(shù)據(jù)庫的原理及結果
[root@db01 scripts]# tree /data /data ├── 3306 │ ├── data │ │ ├── mysql │ │ │ ├── columns_priv.frm │ │ │ ├── columns_priv.MYD │ │ │ ├── columns_priv.MYI │ │ │ ├── db.frm │ │ │ ├── db.MYD │ │ │ ├── db.MYI │ │ │ ├── event.frm │ │ │ ├── event.MYD │ │ │ ├── event.MYI │ │ │ ├── func.frm │ │ │ ├── func.MYD │ │ │ ├── func.MYI …………………省略部分………………………………
（3）初始化故障
示例1：給出了警告信息“WARNING: The host 'db01' could not be looked up with resolveip.”
這個警告信息可以忽略，如果非要解決則需修改主機名解析
echo "172.16.1.52 db01" >>/etc/hosts
8、啟動MySQL多實例數(shù)據(jù)庫
第一個實例3306的啟動命令
/data/3306/mysql start
第二個實例3307的啟動命令
/data/3307/mysql start
現(xiàn)在檢查MySQL多實例數(shù)據(jù)庫是否成功啟動
netstat -lntup|grep 330
操作過程：
[root@db01 scripts]# /data/3306/mysql
Usage: /data/3306/mysql {start|stop|restart}
[root@db01 scripts]# /data/3306/mysql start
Starting MySQL...
[root@db01 scripts]# /data/3307/mysql start
Starting MySQL...查看端口
[root@db01 scripts]# ss -nlutp|grep 330
tcp LISTEN 0 600 *:3306 *:* users:(("mysqld",48766,12))
tcp LISTEN 0 600 *:3307 *:* users:(("mysqld",49510,12))9、配置及管理MySQL多實例數(shù)據(jù)庫
（1）配置MySQL多實例數(shù)據(jù)庫開機自啟動
服務的開機自啟動和關鍵，MySQL多實例的啟動也不例外，把MySQL多實例的啟動命令加入/etc/rc.local，實現(xiàn)開機自啟動：
cat >>/etc/rc.local<提示：要確保MySQL腳本有執(zhí)行權限
（2）登陸mysql測試
登錄時要指定sock文件
測試命令如下：
mysql -S /data/3306/mysql.sock <==直接敲進來了，而且身份還是root，但是多了-S /data/3306/mysql.sock，用戶區(qū)別登錄不同的實例
操作演示[root@db01 scripts]# mysql -S /data/3306/mysql.sock Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.5.52-log Source distribution Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> [root@db01 3306]# mysql -S /data/3307/mysql.sock Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.5.52-log Source distribution Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>到這里MySQL多實例就配置完成啦O(∩_∩)O~~?。?！
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