MySQL數據同步【雙主熱備】

jopen 11年前發布 | 44K 次閱讀 MySQL 數據庫服務器

應用環境

數據庫同步方式

創建數據庫表

配置數據庫my.ini文件

my.ini文件簡單釋義

配置雙向同步

配置項釋義

設置主機并啟動從服務器線程

show slave status

測試同步

解決自增長列的問題

模擬測試自增長列解決方案

故障排除

MySQL版本間復制兼容性問題

ERROR 1201 (HY000)

應用環境

數據庫服務器

虛擬機

OS: Windows Server 2003

1.數據庫服務器242

IP:192.168.206.242

2.數據庫服務器243

IP:192.168.206.243

MySQL版本

版本號：5.5.2

查詢語句：SELECT VERSION();

數據庫同步方式

兩臺服務器互為主從，雙向同步數據

創建數據庫表

為試驗雙向同步，簡單編寫了一個創建數據庫和一個用戶表的語句。

并分別在服務器242和243上的MySQL中執行語句。

CREATE DATABASE wilsondb;

USE wilsondb;

DROP TABLE IF EXISTS `userinfo`;

CREATE TABLE `userinfo` (

  `UserId` int(11) NOT NULL AUTO_INCREMENT,

  `UserName` varchar(64) DEFAULT NULL,

  PRIMARY KEY (`UserId`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

MySQL數據同步【雙主熱備】

配置數據庫my.ini文件

在242和243服務器MySQL的安裝目錄下找到my.ini文件

1.my.ini文件各配置項簡單釋義

my.ini詳情及簡單釋義

# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
#
#
# Installation Instructions
# ----------------------------------------------------------------------
#
# On Linux you can copy this file to /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options
# (@localstatedir@ for this installation) or to
# ~/.my.cnf to set user-specific options.
#
# On Windows you should keep this file in the installation directory
# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
# make sure the server reads the config file use the startup option
# "--defaults-file".
#
# To run run the server from the command line, execute this in a
# command line shell, e.g.
# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
#
# To install the server as a Windows service manually, execute this in a
# command line shell, e.g.
# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
#
# And then execute this in a command line shell to start the server, e.g.
# net start MySQLXY
#
#
# Guildlines for editing this file
# ----------------------------------------------------------------------
#
# In this file, you can use all long options that the program supports.
# If you want to know the options a program supports, start the program
# with the "--help" option.
#
# More detailed information about the individual options can also be
# found in the manual.
#
#
# CLIENT SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.
#
# 客戶端
[client]

# 端口號
port=3306

[mysql]
# 字符集
default-character-set=utf8

# SERVER SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this
# file.
#
[mysqld]

# The TCP/IP Port the MySQL Server will listen on
# MySQL端口號
port=3306

#Path to installation directory. All paths are usually resolved relative to this.
# 安裝路徑
basedir="C:/Program Files/MySQL/MySQL Server 5.5/"

#Path to the database root
# 數據庫根路徑
datadir="C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.5/Data/"

# The default character set that will be used when a new schema or table is
# created and no character set is defined
# 字符集
character-set-server=utf8

# The default storage engine that will be used when create new tables when
# 默認存儲引擎
default-storage-engine=INNODB

# Set the SQL mode to strict
# 設置嚴格SQL模型
# 參數詳細：http://www.cnblogs.com/ainiaa/archive/2010/12/31/1923002.html
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"

# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.
# 服務器端最大并發數，一個是留給超級管理員權限登錄數據庫
max_connections=100

# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
# 查詢緩存的大小，Note：在查詢常變，表結構常變的情況下，用緩存反而不好
query_cache_size=0

# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]
# Table高速緩存的數量
table_cache=256

# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
# 單張臨時表的大小限制
tmp_table_size=26M

# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before. This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
# 緩存多少線程給客戶端使用
thread_cache_size=8

#*** MyISAM Specific options

# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
# 重建索引時臨時文件允許的最大值
myisam_max_sort_file_size=100G

# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method. This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
# 表發生變化重新排序需要的緩沖大小
myisam_sort_buffer_size=52M

# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
# MyISAM表索引緩存大小，建議不要超過可用內存的30%
key_buffer_size=8M

# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
# MyISAM表全表掃描時的緩沖區大小（順序讀取）
read_buffer_size=64K
# 隨機讀取的緩沖區大小
read_rnd_buffer_size=256K

# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.
# 排序使用的緩沖區大小
sort_buffer_size=256K

#*** INNODB Specific options ***

# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.
#skip-innodb

# Additional memory pool that is used by InnoDB to store metadata
# information. If InnoDB requires more memory for this purpose it will
# start to allocate it from the OS. As this is fast enough on most
# recent operating systems, you normally do not need to change this
# value. SHOW INNODB STATUS will display the current amount used.
# 設置InnoDB存儲引擎存放數據字典信息和內部數據結構的內存大小
innodb_additional_mem_pool_size=4M

# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.
# N（N是后面設置的值）次事務提交或事務外的指令就需要把日志寫入硬盤
innodb_flush_log_at_trx_commit=1

# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).
# 設置InnoDB存儲引擎的事務日志使用的緩沖區
innodb_log_buffer_size=1520K

# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system. Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.
# 設置InnoDB存放索引和表數據的最大緩沖區大小
innodb_buffer_pool_size=147M

# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.
# 一個InnoDB事條日志的大小
innodb_log_file_size=74M

# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
# InnoDB最大并發線程數
innodb_thread_concurrency=8

PS: 上面的折疊代碼試驗在chrome瀏覽器下需要手動刷一下頁面才能展開

2.配置雙向同步

242服務器上配置：

在[mysqld]這個Section中加入如下key/value對：

#---------------------------------------------

server-id=242

log-bin=mysql-bin

relay-log=relay-bin

relay-log-index=relay-bin-index

replicate-do-db=wilsondb

#---------------------------------------------

243服務器上配置：

在[mysqld]這個Section中加入如下key/value對：

#---------------------------------------------

server-id=243

log-bin=mysql-bin

relay-log=relay-bin

relay-log-index=relay-bin-index

replicate-do-db=wilsondb

#---------------------------------------------

3.配置項釋義【復制啟動選項】

① server-id：標識，唯一，值范圍在：1至2^23-1

② log-bin：配置是否在數據庫有變動時寫二進制日志

查看日志是否開啟：

show variables like '%bin';

MySQL數據同步【雙主熱備】

③ relay-log：這個不太會解釋，Master二進制日志到Slave的IO進程會寫到relay-log最后一行，Slave的sql進程時刻監測著relay-log是否有變化，有變化則解析執行.

④ replicate-to-db:同步的數據庫

⑤ 其它復制啟動選項： http://dev.mysql.com/doc/refman/5.1/zh/replication.html#replication-options

在服務器242和243上配置好之后，分別重啟MySQL服務，如果重啟失敗則說明配置有誤!

MySQL數據同步【雙主熱備】

設置主機并啟動從服務器線程

服務242上用MySQL命令行工具執行如下語句：

mysql> stop slave;

mysql> change master to master_host='192.168.206.243',master_user='root',master_password='abcd';

mysql> start slave;

mysql> show slave status\G;

#master_host的最大長度為60

#master_user的最大長度為16

#master_password最大長度為32

服務243上上用MySQL命令行工具執行如下語句：

mysql> stop slave;

mysql> change master tomaster_host='192.168.206.242',master_user='root',master_password='abcd';

mysql> start slave;

mysql> show slave status\G;

Show Slave Status 部分釋義

① Slave_IO_Status:線程已經連接上主服務器，正等待二進制日志事件到達。如果主服務器正空閑，會持續較長的時間。如果等待持續slave_read_timeout秒，則發生超時。此時，線程認為連接被中斷并企圖重新連接。

更多Slave_IO_Status: http://dev.mysql.com/doc/refman/5.1/zh/replication.html#slave-io-thread-states

② Master_Host: 主機IP

③ Master_Log_File和Master_LOG_POS選項執行CHANGE MASTER TO來告訴從服務器重新從該點讀取二進制日志

④ Slave_IO_Running:是否要從Master復制二進制數據

⑤ Slave_SQL_Running:是否執行從Master復制過來的二進制數據

⑥ Slave_IO_Running和Slave_SQL_Running的值均為Yes時為同步開啟;

⑦ Last_Errno和Last_Error是錯誤信息的提示（如果有錯誤）

⑧ Seconds_Behind_Master：Slave的數據落后Master的多少秒，同步完成為0

測試同步

  為了方便測試，裝了一個Navicat for MySQL;

  對242和243數據庫進行了雙向的增、刪、改操作;

結果：最后都能正確的雙向同步。

解決自增長列的問題

原因：當同步斷開，兩臺服務器分別有新數據進入，那么主鍵ID是自增長列會出現沖突的情況，會導致同步無法繼續。

在242和243服務器MySQL的安裝目錄下找到my.ini文件

分別在文件最后添入下面配置項：

服務器242：

#-------------------------------------

auto_increment_offset=1

auto_increment_increment=2

#-------------------------------------

服務器243：

#-------------------------------------

auto_increment_offset=2

auto_increment_increment=2

#-------------------------------------

查看修改后的屬性值：

SHOW VARIABLES LIKE 'auto_inc%';

服務器242：

服務器243：

通過調整auto_increment_offset和auto_increment_increment讓兩臺服務器自增長值不重復，這樣多臺服務器自增的問題就解決了;

（此項操作為了看自增更明顯，我重新生成了表，然后再做了配置，其實本不需要重新生成表結構!）

模擬測試自增長列解決方案

測試過程模擬同步在斷開后，兩個數據庫分別都有數據插入，然后再開啟同步，是否會有自增ID的沖突。

1.先分別在服務器242和243上停止Slave線程

2.然后分別向服務器242和243所在數據庫中分別插入數據

很明顯，分別插入時，自增列也不會重復;

3.分別開啟服務器242和243的Slave線程

4.查看同步后的數據

-------------------------------------------------------------

大功告成，同步成功，且沒有發生沖突！

故障排除

試驗過程中遇到幾個主要問題：

1.MySQL版本間復制兼容性

     官方是推薦使用最近的版本，復制功能在不斷改進中，同時推薦主從服務器使用相同的版本;

為了避免出現一些兼容性的問題，這里兩臺數據庫服務器上的MySQL安裝了相同的版本;

     不同MySQL版本之間的復制兼容性: http://dev.mysql.com/doc/refman/5.1/zh/replication.html#replication-compatibility

2.ERROR 1201 (HY000): Could not initialize master info structure; more error messages can be found in the MySQL error log

     在start slave;時出現error 1201(HY000)，出錯后注意用show slave status\G 看錯誤提示（Last_IO_Error和Last_SQL_Error）。后臺根據提示定位是在沒關掉同步的情況下進行了一些沖突的SQL操作，

解決步驟： ① 停止SQL服務

  ② 刪除master.info和relay-log.info文件

  ③ change master to master_host='XXXXXX',

  master_user='XXXX',master_password='XXXX';

  ④ 重啟SQL服務器，再start slave;

  過程中遠不止遇到這幾個錯誤，沒記錄下細節，都是看相關提示修正的，都是些操作問題或者是細心問題;