1、MySQL的多实例：
多实例的特点：能够有效地利用服务器的资源，节约服务器的资源
MySQL多实例的配置有两种，第一是使用一个配置文件，这种方法不推荐使用，容易出错；第二种是用多个配置文件，这种方法的好处是可以方便管理。
[root@localhost 3308]# tree -L 2 /data/
/data/
├── 3307
│   ├── data
│   ├── my.cnf
│   ├── mysql
│   ├── mysql_3307.err
│   ├── mysqld.pid
│   └── mysql.sock
└── 3308
    ├── data
    ├── my.cnf
    ├── mysql
    ├── mysql_3308.err
    ├── mysqld.pid
    └── mysql.sock

安装mysql
通过压缩包哦安装，提前下载mysql-5.5.62-linux-glibc2.12-x86_64.tar.gz，解压即可。
添加mysql用户，
useradd -s /sbin/nologin mysql

将解压的文件移动到/usr/local并做软连接
mv mysql-5.5.62-linux-glibc2.12-x86_64 /usr/local
ln -s mysql-5.5.62-linux-glibc2.12-x86_64 /usr/local/mysql

创建每个服务端口的data文件夹
mkdir -p /data/{3307,3308}

进行mysql初始化：
./scripts/mysql_install_db --user=mysql --basedir=/application/mysql/ --datadir=/data/3307/data
./scripts/mysql_install_db --user=mysql --basedir=/application/mysql/ --datadir=/data/3308/data

配置端口的配置文件my.cnf
vim /data/3307/my.cnf
vim /data/3308/my.cnf
[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 = 8

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
3308的配置文件把3307改成3308

配置各端口的启动文件
vim /data/3307/mysql
vim /data/3308/mysql
[3307/mysql]
#!/bin/bash
# chkconfig: 2345 21 60
# description: msyql start scripts
port=3307
user=root
passwd=123456
path=/application/mysql/bin
#socket=/tmp/mysql.sock
mysqlso