能否将不同机器上的不同库中的表同步到同一个机器的同一个库中？表是不同的.而且对于slave这台机子来说,这些表只用来读.

同步不同库的表很简单了,用

replicate-do-table=db_name.tbl_name

多个不同机子上的不同库的表同步到同一个机子的同一个库中,再加上下面这句.

replicate-rewrite-db=from_name->to_name

配置slave 上的my.cnf

cat my.cnf

[mysqld_multi]

mysqld = /usr/local/mysql/bin/mysqld_safe

mysqladmin = /usr/local/mysql/bin/mysqladmin

[mysqld1]

port     = 3306

socket   = /tmp/mysql.sock1

skip-locking

pid-file=/usr/local/mysql/data/test-db1a.pid

datadir = /usr/local/mysql/data

log=/usr/local/mysql/data/test-db1.log

user = mysql

log-slow-queries=/usr/local/mysql/data/slowquery1.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   =   192.168.0.1

master-user   =   'replcate'

master-password =   '1234567890'

master-port   = 3306

report-host = test-db3

master-connect-retry = 30

log-bin

log-slave-updates

replicate-rewrite-db=from_name->to_name

replicate-do-table=db_name.tbl_name

[mysqld2]

port = 3307

socket = /tmp/mysql.sock2

pid-file = /usr/local/mysql/data/test-db2b.pid

datadir = /usr/local/mysql/data

log=/usr/local/mysql/data/test-db2.log

user = mysql

log-slow-queries=/usr/local/mysql/data/slowquery2.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   =   192.168.0.2

master-user   =   'repl'

master-password =   '1234567890'

master-port   = 3307

report-host = test-db3

master-connect-retry = 30

log-bin

log-slave-updates

replicate-rewrite-db=from_name->to_name

replicate-do-table=db_name.tbl_name

好了,看看上面配置,明白了两个mysqld实例用了相同的库表文件,会不会有问题呢?

当然,使用不当的话会有问题,首先要符合两个实例读写的对象没有交叉.(同步过来的表唯一),其次选择合适的存储引擎,MYISM比innodb从理论上更适合这种应用．再次使用过程中对slave上的两个mysqld实例，只使用一个进行本机其它库表(非同步过来的)写操作．

ok,这种解决方案已通过测试．