linux系统下实现MySQL主从热备份

页面导航:首页 > 数据库 > Mysql > linux系统下实现MySQL主从热备份

linux系统下实现MySQL主从热备份

来源: 作者: 时间:2016-02-03 08:56 【

主从的作用:1 可以当做一种备份方式2 用来实现读写分离,缓解一个数据库的压力MySQL主从备份原理:Mysql的主从复制至少是需要两个Mysql的服务,当然Mysql的服务是可以分布在不同的服

主从的作用:

1.可以当做一种备份方式

2.用来实现读写分离,缓解一个数据库的压力

 

MySQL主从备份原理:

Mysql的主从复制至少是需要两个Mysql的服务,当然Mysql的服务是可以分布在不同的服务器上,也可以在一台服务器上启动多个服务。

如果想配置成为同一台上的话,注意安装的时候,选择两个不同的prefix=路径,同时开启服务器的时候,端口不能相同。

(1)首先确保主从服务器上的Mysql版本相同(做主从服务器的原则是,MYSQL版本要相同,如果不能满足,最起码从服务器的MYSQL的版本必须高于主服务器的MYSQL版本 )

(2)在主服务器上,设置一个从数据库的账户,使用REPLICATION SLAVE赋予权限,如:

 

mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave001'@'192.168.0.99' IDENTIFIED BY

'123456';

Query OK, 0 rows affected (0.13 sec)

[原理]master 上提供binlog ,

slave 通过 I/O线程从 master拿取 binlog,并复制到slave的中继日志中

slave 通过 SQL线程从 slave的中继日志中读取binlog ,然后解析到slave中

 

主从复制大前提

需要master与slave同步,因为笔者的数据库数据量不大,所以无需考虑太多,直接把

master上的data复制到了slave上,但是如果是大的数据量,比如像taobao这个的系统

那么数据同步也是很难得,需要有一个完善的方案,有兴趣的可以看看这篇文章

http://www.taobaodba.com/html/564_%E5%A2%9E%E9%87%8F%E6%97%A5%E5%BF%97%E8%BF%AD%E4%BB%A3%E5%90%8C%E6%AD%A5%E5%92%8C%E9%98%BF%E5%9F%BA%E9%87%8C%E6%96%AF%E6%82%96%E8%AE%BA.html

 

实验环境准备:

OS: CentOS5.4

Mysql:Mysql-5.0.41.tar.gz
辅助工具:SSH Secure Shell Client

两台测试IP&服务器:
Master Server: 192.168.1.2/Linux CentOS5.4/MYSQL 5.0
Slave Server: 192.168.1.3/Linux CentOS5.4/MYSQL 5.0

 

安装配置步骤:

 

1、首先在Linux环境下分配好磁盘分区以便留足MySQL数据库的备份空间

[[email protected] mysql]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/simfs 30G 2.0G 29G 7% /

 

2、MySQL数据库的安装:

1>将Mysql-5.0.41.tar.gz通过SSH 工具 上传到Linux系统的home目录下

2>建立MySQL使用者和群组:

#groupadd mysql
#useradd -g mysql mysql
3>解压缩Mysql-5.0.41.tar.gz源码包

#cd /usr/local/sofrware
#tar zxvf Mysql-5.0.41.tar.gz

4>进入源码目录编译安装

#cd /home/Mysql-5.0.41
#./configure --prefix=/usr/local/mysql --with-charset=gbk |注:配置Mysql安装路径并且支持中文
#make |注:编译
#make install |注:编译安装

5>替换/etc/my.cnf文件,进入源码包,执行命令

#cd /home/Mysql-5.0.41
#cp support-files/my-medium.cnf /etc/my.cnf

6>完成以上操作以后进行初始化数据库,进入已经安装好的mysql目录

#cd /usr/local/mysql
#bin/mysql_install_db --user=mysql |注:--user=mysql 初始化表并且规定用mysql用户

7>设置给mysql和root用户设定访问权限 我们先进入mysql目录

#cd /usr/local/mysql
#chown -R root /usr/local/mysql      注:设定root能访问/usr/local/mysq
#chown -R mysql /usr/local/mysql/var   注:设定mysql用户能访问/usr/local/mysql/var
#chgrp -R mysql /usr/local/mysql     注:设定mysql组能够访问/usr/local/mysq
8>启动mysql,进入已经安装好的目录

#cd /usr/local/mysql
#bin/mysqld_safe --user=mysql &

9>
修改mysql数据库超级用户root的缺省密码:
/usr/local/mysql/bin/mysqladmin -u root password 'mysql'

关闭mysql服务器
cd /usr/local/mysql/bin
./mysqladmin -u root -p shutdown

10>设定开机就启动mysql,进入源码目录下

# cd /home/Mysql-5.0.41
# cp support-files/mysql.server /etc/init.d/mysql

# chmod +x /etc/init.d/mysql
# chkconfig --level 345 mysql on
# service mysql restart
Shutting down MySQL. [ 确定 ]
Starting MySQL [ 确定 ]
[[email protected] mysql]#
到这里MySQL就装好了。
 

3、配置MySQL5.0的复制(Replication)功能

 

一.将master设置为只读。

mysql> flush tables with read lock;

二.用master中的data文件夹替换slave中的data文件夹

比如 用 tar zcvf mysql_data.gz /media/raid10/mysql/3306/data

然后 mv mysql_data.gz /media/raid10/htdocs/blog/wordpress/

因为我的 /media/raid10/htdocs/blog/wordpress/ 是 Nginx 的主目录

所以可以在 slave上,用wget这个文件,然后 解压,并覆盖slave上的data文件

注意:覆盖之前最好备份源文件

 

三.配置master的my.cnf,添加以下内容

 

在[mysqld]配置段添加如下字段

server-id=1

log-bin=/media/raid10/mysql/3306/binlog/binlog //这里写你的binlog绝对路径名

binlog-do-db=blog //需要同步的,如果没有本行,即表示同步所有的数据库

binlog-ignore-db= //被忽略的数据库

 

这里给出我的my.cnf配置文件

[client]

character-set-server = utf8

port = 3306

socket = /tmp/mysql.sock

 

[mysqld]

character-set-server = utf8

replicate-ignore-db = mysql

replicate-ignore-db = test

replicate-ignore-db = information_schema

user = mysql

port = 3306

socket = /tmp/mysql.sock

basedir = /usr/local/webserver/mysql

datadir = /media/raid10/mysql/3306/data

log-error = /media/raid10/mysql/3306/mysql_error.log

pid-file = /media/raid10/mysql/3306/mysql.pid

open_files_limit = 10240

back_log = 600

max_connections = 5000

max_connect_errors = 6000

table_cache = 614

external-locking = FALSE

max_allowed_packet = 16M

sort_buffer_size = 1M

join_buffer_size = 1M

thread_cache_size = 300

#thread_concurrency = 8

query_cache_size = 20M

query_cache_limit = 2M

query_cache_min_res_unit = 2k

default-storage-engine = MyISAM

thread_stack = 192K

transaction_isolation = READ-COMMITTED

tmp_table_size = 20M

max_heap_table_size = 20M

long_query_time = 3

log-slave-updates

log-bin = /media/raid10/mysql/3306/binlog/binlog

binlog-do-db=blog

binlog-ignore-db=mysql

 

binlog_cache_size = 4M

binlog_format = MIXED

max_binlog_cache_size = 8M

max_binlog_size = 20M

relay-log-index = /media/raid10/mysql/3306/relaylog/relaylog

relay-log-info-file = /media/raid10/mysql/3306/relaylog/relaylog

relay-log = /media/raid10/mysql/3306/relaylog/relaylog

expire_logs_days = 30

key_buffer_size = 10M

read_buffer_size = 1M

read_rnd_buffer_size = 6M

bulk_insert_buffer_size = 4M

myisam_sort_buffer_size = 8M

myisam_max_sort_file_size = 20M

myisam_repair_threads = 1

myisam_recover

 

interactive_timeout = 120

wait_timeout = 120

 

skip-name-resolve

#master-connect-retry = 10

slave-skip-errors = 1032,1062,126,1114,1146,1048,1396

 

#master-host = 192.168.1.2

#master-user = username

#master-password = password

#master-port = 3306

 

server-id = 1

 

innodb_additional_mem_pool_size = 16M

innodb_buffer_pool_size = 20M

innodb_data_file_path = ibdata1:56M:autoextend

innodb_file_io_threads = 4

innodb_thread_concurrency = 8

innodb_flush_log_at_trx_commit = 2

innodb_log_buffer_size = 16M

innodb_log_file_size = 20M

innodb_log_files_in_group = 3

innodb_max_dirty_pages_pct = 90

innodb_lock_wait_timeout = 120

innodb_file_per_table = 0

 

#log-slow-queries = /media/raid10/mysql/3306/slow.log

#long_query_time = 10

 

[mysqldump]

quick

max_allowed_packet = 32M

 

四.在master机上为slave机添加一同步帐号

mysql> grant replication slave on *.* to 'admin'@'172.29.141.115' identified by '12345678';

mysql> flush privileges ;

 

五.配置slave的my.cnf,添加以下内容

注意:

1.如果mysql是5.5.3-m3 的版本,只需

在[mysqld]字段下添加如下内容

server-id=2

 

2.如果是5.0x的版本,需要

在[mysqld]字段下添加如下内容

server-id=2

log-bin=mysql-bin //这是同步的binlog,具体以你的binlog为准

master-host=172.29.141.112

master-user=admin

master-password=12345678

master-port=3306

master-connect-retry=60 //如果发现主服务器断线,重新连接的时间差;

replicate-do-db=blog //同步的数据库,不写本行 表示 同步所有数据库

replicate-ignore-db=mysql //不需要备份的数据库

log-slave-update

slave-skip-errors

 

我的mysql是5.5.3,这里给出我的slave my.cnf配置文件

[client]

character-set-server = utf8

port = 3306

socket = /tmp/mysql.sock

 

[mysqld]

character-set-server = utf8

replicate-ignore-db = mysql

replicate-ignore-db = test

replicate-do-db = blog

replicate-ignore-db = information_schema

user = mysql

port = 3306

socket = /tmp/mysql.sock

basedir = /usr/local/webserver/mysql

datadir = /media/raid10/mysql/3306/data

log-error = /media/raid10/mysql/3306/mysql_error.log

pid-file = /media/raid10/mysql/3306/mysql.pid

open_files_limit = 10240

back_log = 600

max_connections = 5000

max_connect_errors = 6000

table_cache = 614

external-locking = FALSE

max_allowed_packet = 16M

sort_buffer_size = 1M

join_buffer_size = 1M

thread_cache_size = 300

#thread_concurrency = 8

query_cache_size = 20M

query_cache_limit = 2M

query_cache_min_res_unit = 2k

default-storage-engine = MyISAM

thread_stack = 192K

transaction_isolation = READ-COMMITTED

tmp_table_size = 20M

max_heap_table_size = 20M

long_query_time = 3

log-slave-updates

log-bin = /media/raid10/mysql/3306/binlog/binlog

binlog_cache_size = 4M

binlog_format = MIXED

max_binlog_cache_size = 8M

max_binlog_size = 20M

relay-log-index = /media/raid10/mysql/3306/relaylog/relaylog

relay-log-info-file = /media/raid10/mysql/3306/relaylog/relaylog

relay-log = /media/raid10/mysql/3306/relaylog/relaylog

expire_logs_days = 30

key_buffer_size = 10M

read_buffer_size = 1M

read_rnd_buffer_size = 6M

bulk_insert_buffer_size = 4M

myisam_sort_buffer_size = 8M

myisam_max_sort_file_size = 20M

myisam_repair_threads = 1

myisam_recover

interactive_timeout = 120

wait_timeout = 120

 

skip-name-resolve

#master-connect-retry = 60

slave-skip-errors = 1032,1062,126,1114,1146,1048,1396

 

#master-host=172.29.141.112

#master-user = admin

#master-password = 12345678

#master-port = 3306

server-id = 2

innodb_additional_mem_pool_size = 16M

innodb_buffer_pool_size = 20M

innodb_data_file_path = ibdata1:56M:autoextend

innodb_file_io_threads = 4

innodb_thread_concurrency = 8

innodb_flush_log_at_trx_commit = 2

innodb_log_buffer_size = 16M

innodb_log_file_size = 20M

innodb_log_files_in_group = 3

innodb_max_dirty_pages_pct = 90

innodb_lock_wait_timeout = 120

innodb_file_per_table = 0

 

#log-slow-queries = /media/raid10/mysql/3306/slow.log

#long_query_time = 10

 

[mysqldump]

quick

max_allowed_packet = 32M

 

六.通过查看master的状态(在master上查看),为配置slave做准备

mysql> show master status/G;

ERROR 2006 (HY000): MySQL server has gone away

No connection. Trying to reconnect...

Connection id: 13

Current database: blog

*************************** 1. row ***************************

File: binlog.000005

Position: 592

Binlog_Do_DB: blog

Binlog_Ignore_DB: mysql

1 row in set (0.01 sec)

 

ERROR:

No query specified

 

从上面的信息,可以看出,master现在使用的binlog是binlog.000005,position是592,那么下面的slave配置必须与这个对应。

 

其实binlog.000005是当前master使用的binlog日志文件

position是当前master使用的binlog.000005日志文件的位置

简单理解为master正在使用哪个binlog的哪个数据行(位置)。

 

七.如果是5.5.3-m3版本mysql,需要启动slave后,配置与master相关对应的信息(在slave上配置)

注意,这个与第六步相对应

 

mysql> stop slave ;

mysql> change master to master_host='172.29.141.112', master_user='admin', master_password='12345678', master_log_file='binlog.000005', master_log_pos=488;

 

mysql> CHANGE MASTER TO MASTER_CONNECT_RETRY=60;

 

这个与5.0的配置my.cnf作用是一样的,配置成与master相对应的内容

主要是配置slave,让slave知道从master的哪个binlog上的哪个位置复制数据。所以需要知道master的ip,user_name,user_passwd,binlog,binlog_position以及多长时间连接一次master

 

八.开启slave

mysql> start slave;

 

九.解除master只读限制,并做测试

mysql> unlock tables;

mysql> use blog;

mysql> create longxibendi ( a int, b int );

 

十.从slave上查看

mysql> use blog;

mysql> show tables;

+-----------------------+

| Tables_in_blog |

+-----------------------+

| longxibendi |

| wp_commentmeta |

| wp_comments |

| wp_links |

| wp_options |

| wp_postmeta |

| wp_posts |

| wp_term_relationships |

| wp_term_taxonomy |

| wp_terms |

| wp_usermeta |

| wp_users |

+-----------------------+

12 rows in set (0.00 sec)

 

可以看到成功了!!

 

十一.配置过程中,可以用 show slave status/G; 在 slave上

查看 slave的复制情况

十二.如果出现什么问题,可能是防火墙的问题

/etc/init.d/iptables stop 关闭 master 上的防火墙,或者进行相应的配置

常遇到的错误与解决:

1.[mysql]ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

这个错误,网上有很多说法,其实直接的原因是mysql服务器没有启动

之前我按照5.0x配置master-slave,然后启动slave,在连接slave,就会报这个错误

后来发现原因是,mysql slave没有启动起来,然后去查错误日志,发现以下的字段

110505 01:55:20 mysqld_safe mysqld from pid file /media/raid10/mysql/3306/mysql.pid ended

110505 02:04:41 mysqld_safe Starting mysqld daemon with databases from /media/raid10/mysql/3306/data

InnoDB: The InnoDB memory heap is disabled

InnoDB: Mutexes and rw_locks use InnoDB's own implementation

110505 2:04:41 InnoDB: highest supported file format is Barracuda.

110505 2:04:41 InnoDB Plugin 1.0.6 started; log sequence number 44338

110505 2:04:41 [ERROR] /usr/local/webserver/mysql/libexec/mysqld: unknown variable 'master-connect-retry=60'

110505 2:04:41 [ERROR] Aborting

110505 2:04:41 InnoDB: Starting shutdown...

110505 2:04:43 InnoDB: Shutdown completed; log sequence number 44348

110505 2:04:43 [Note] /usr/local/webserver/mysql/libexec/mysqld: Shutdown complete

 

110505 02:04:43 mysqld_safe mysqld from pid file /media/raid10/mysql/3306/mysql.pid ended

110505 02:07:44 mysqld_safe Starting mysqld daemon with databases from /media/raid10/mysql/3306/data

InnoDB: The InnoDB memory heap is disabled

InnoDB: Mutexes and rw_locks use InnoDB's own implementation

110505 2:07:44 InnoDB: highest supported file format is Barracuda.

110505 2:07:45 InnoDB Plugin 1.0.6 started; log sequence number 44348

110505 2:07:45 [ERROR] /usr/local/webserver/mysql/libexec/mysqld: unknown variable 'master-host=172.29.141.112'

110505 2:07:45 [ERROR] Aborting

从上面的ERROR,知道 master-connect-retry=60这个my.cnf中的参数有问题,后来从网上搜资料,发现,mysql5.5.3-m3版本不支持这个参数,

然后我把这个参数注释掉,又发现不支持这个参数master-host,从上面的ERROR字段可以看出来。后来,就知道,5.5.3-m3不能按5.0.x那样配置

原来不需要从my.cnf中配置master相关信息,当然server-id是必须的。其他信息,通过 在命令行中 ,登陆 mysql服务器配置。

其实server-id的作用是

第一,标识,区分不同的slave,第二,防止环备份的发生

 

2.Last_Error: Last_SQL_Error:等错误

这个是从 slave上,运行 show slave status/G; 得到的。出现这个问题,最根本的原因是,slave 没有与当前的master的binlog 和binlog的position对应上

也就是说,slave传输的master binlog 不与当前master正使用的binlog以及binlog的行数对应。

 

3.[ERROR] Slave I/O: error connecting to master ':3306' - retry-time: 60 retries: 86400, Error_code: 2003

这个就是因为防火墙的问题,所以用 /etc/init.d/iptables stop 关闭防火墙就OK了。

 

4.遇到ERROR 2013 (HY000): Lost connection to MySQL server during query错误。
在/ect/my.cnf的[mysqld]中添加skip-name-resolve

 

 

Tags:

文章评论

最 近 更 新
热 点 排 行
Js与CSS工具
代码转换工具

<