第三部分, 在一台服务器构建多mysql 从服务。
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构建从服务器的预选准备: 建议用mysqld_multi 把主服务器的mysql全部停掉.删除数据目录中的所有除数据库目录以外的任何文件(此文中的数据目录库有４个,datadir = /usr/local/mysql/中的 data1 -- data1)．建主从都用相同的数据目录路径．
用Tar 命令把每数据库封装起来，并通过sftp命令put/get到从服务器(db-app1 192.168.0.101)。
下列操作供参考:
在db-app主机上的操作
db-app:/ # tar -cf data1.tar /usr/local/mysql/data1
db-app:/ # tar -cf data2.tar /usr/local/mysql/data2
db-app:/ # tar -cf data3.tar /usr/local/mysql/data3
db-app:/ # tar -cf data4.tar /usr/local/mysql/data4
在db-app1主机上的操作
db-app1:/ # tar xvf data1.tar
db-app1:/ # tar xvf data2.tar
db-app1:/ # tar xvf data3.tar
db-app1:/ # tar xvf data4.tar
同时，请确认系统帐号mysql是否对主/从服务器的中的mysql数据目录都有操作权限，如果无法确认，你直接更修改这些目录的所有权即可。
在db-app主机上的操作
db-app:/ # chown mysql.mysql /usr/local/mysql/data1 -R
db-app:/ # chown mysql.mysql /usr/local/mysql/data2 -R
db-app:/ # chown mysql.mysql /usr/local/mysql/data3 -R
db-app:/ # chown mysql.mysql /usr/local/mysql/data4 -R
在db-app1主机上的操作
db-app1:/ # chown mysql.mysql /usr/local/mysql/data1 -R
db-app2:/ # chown mysql.mysql /usr/local/mysql/data2 -R
db-app3:/ # chown mysql.mysql /usr/local/mysql/data3 -R
db-app4:/ # chown mysql.mysql /usr/local/mysql/data4 -R
下面就是从服务器上/etc/my.cnf的全部内容。
提示:下面的my.cnf中将会提到一个帐号:repl, 口令为:1234567890, 这个帐号就是上面专门建立的。
其实都一样,主要是修改my.cnf中的内容,让每个从mysql通过主mysql的不同的端口,去获取各自bin-log来更新自生的数据库内容．现贴上我的my.cnf全部内容(从服务器),相关参数与请参考mysql 官文手册。
#[client]
#password = your_password
#port = 3306
#socket = /tmp/mysql.sock
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = mysql
password = netmoniit
[mysqld1]
port = 3306
socket = /tmp/mysql.sock1
skip-locking
pid-file=/usr/local/mysql/data/net-app1a.pid
datadir = /usr/local/mysql/data
log=/usr/local/mysql/data/net-app1.log
user = mysql
log-slow-queries=/usr/local/mysql/data/slowquery.log
long_query_time = 2
key_buffer = 256M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
myisam_sort_buffer_size = 64M
thread_cache = 32
query_cache_size = 32M
thread_concurrency = 2
max_connections=500
server-id = 2
master-host = 192.168.0.100
master-user = repl
master-password = 1234567890
master-port = 3309
report-host = net-app1
master-connect-retry = 30
log-bin
log-slave-updates
[mysqld2]
port = 3307
socket = /tmp/mysql.sock2
pid-file = /usr/local/mysql/data2/net-app1b.pid
datadir = /usr/local/mysql/data2
log=/usr/local/mysql/data2/net-app1.log
user = mysql
log-slow-queries=/usr/local/mysql/data2/slowquery.log
long_query_time = 10
key_buffer = 128M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 1M
read_buffer_size = 1M
myisam_sort_buffer_size = 32M
thread_cache = 32
query_cache_size = 16M
thread_concurrency = 2
max_connections=300
server-id = 2
master-host = 192.168.0.100
master-user = repl
master-password = 1234567890
master-port = 3309
report-host = net-app1
master-connect-retry = 30
log-bin
log-slave-updates
[mysqld3]
port = 3308
socket = /tmp/mysql.sock3
pid-file = /usr/local/mysql/data3/net-app1c.pid
datadir = /usr/local/mysql/data3
log=/usr/local/mysql/data3/net-app1.log
user = mysql
log-slow-queries=/usr/local/mysql/data3/slowquery.log
long_query_time = 10
key_buffer = 128M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 1M
read_buffer_size = 1M
myisam_sort_buffer_size = 32M
thread_cache = 32
query_cache_size = 16M
thread_concurrency = 2
max_connections=300
server-id = 2
master-host = 192.168.0.100
master-user = repl
master-password = 1234567890
master-port = 3309
report-host = net-app1
master-connect-retry = 30
log-bin
log-slave-updates
[mysqld3]
port = 3308
socket = /tmp/mysql.sock4
pid-file = /usr/local/mysql/data4/net-app1d.pid
datadir = /usr/local/mysql/data4
log=/usr/local/mysql/data4/net-app1.log
user = mysql
log-slow-queries=/usr/local/mysql/data4/slowquery.log
long_query_time = 10
key_buffer = 128M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 1M
read_buffer_size = 1M
myisam_sort_buffer_size = 32M
thread_cache = 32
query_cache_size = 16M
thread_concurrency = 2
max_connections=300
server-id = 2
master-host = 192.168.0.100
master-user = repl
master-password = 1234567890
master-port = 3309
report-host = net-app1
master-connect-retry = 30
log-bin
log-slave-updates
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[isamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout |
在功告成,现在分别启动两台主机上的多mysql服务，这样，每个主服务的每个mysql有变化，都会自动复制／更新到从服务器对应的数据库中。
db-app:/ # /usr/local/mysq/bin/mysqld_multi --config-file=/etc/my.cnf start 1-4
db-app1:/ # /usr/local/mysq/bin/mysqld_multi --config-file=/etc/my.cnf start 1-4
