ubuntu修改mysql默认路径和修改max_connect参数

由于老需要搭建不同区域的mysql，而RDS有的时候又不想用。原因当然是比自己搭建的贵啦不少啦= =。

记录下正在使用的mysql5.7配置：

#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.

# Here is entries for some specific programs
# The following values assume you have at least 32M ram

[mysqld_safe]
socket = /var/run/mysqld/mysqld.sock
nice = 0

[mysqld]
#sql_mode =STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
#sql_mode = NO_ENGINE_SUBSTITUTION
#
# * Basic Settings
#
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /data/mysql
datadir = /data/mysql
tmpdir = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer_size = 200M
max_allowed_packet = 16M
low_priority_updates=1
thread_stack = 192K
thread_cache_size = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover-options = BACKUP
#最大连接数
max_connections = 4000
#table_cache = 64
#table缓存
table_open_cache=2000
table_open_cache_instances=16
#thread_concurrency = 10
#
# * Query Cache Configuration
#
#查询缓存
query_cache_limit = 128M
query_cache_type=1
query_cache_size = 528M

innodb_file_per_table
innodb_log_files_in_group=3
innodb_open_files=4000

#http://blog.csdn.net/qing_gee/article/details/42742241
innodb_buffer_pool_size=2G
innodb_buffer_pool_instances=1
#http://blog.csdn.net/wei_wenbo/article/details/50817751
join_buffer_size=32K
sort_buffer_size=32K
innodb_checksums=0
innodb_doublewrite=0
innodb_support_xa=0
innodb_thread_concurrency=0
innodb_flush_log_at_trx_commit=2
innodb_max_dirty_pages_pct=50
innodb_use_native_aio=1
innodb_stats_persistent = 1
innodb_adaptive_flushing = 1
innodb_flush_neighbors = 0
innodb_read_io_threads = 4
innodb_write_io_threads = 4
innodb_io_capacity = 4000
innodb_purge_threads=1
innodb_adaptive_hash_index=0
innodb_monitor_enable = '%'
performance_schema=OFF
#innodb_spin_wait_delay= 6 / 96
#innodb_additional_mem_pool_size=20M
#innodb_log_file_size=1024M
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file = /var/log/mysql/mysql.log
#general_log = 1
#
# Error log - should be very few entries.
#
log_error = /data/mysql/sql_error.log
#
# Here you can see queries with especially long duration
#log_slow_queries = /var/log/mysql/mysql-slow.log
#long_query_time = 2
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#server-id = 1
#log_bin = /data/mysql/logs/mysql-bin.log
#expire_logs_days = 10
max_binlog_size = 100M
#binlog_do_db =
#binlog_ignore_db = include_database_name
#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!
#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem


以上配置有的是博主从各个业务场景需求中添加的，有的是网上查询的配置，不一定是最优的，但在测试和较小的并发下效果还是不错的。

这里有些地方需要注意：baseDir和max_connect被修改过，这两个值也是需要点额外操作的，直接修改无效。记录一下因为查资料了很多次。博主只会ubuntu，所以以ubuntu为主。

设置mysql存放目录

#1. 设置新的数据存放路径，：
mkdir -p /data/mysql
#2.复制原有数据
cp -R /var/lib/mysql/* /data/mysql
#3.修改权限
chown -R mysql:mysql /data/mysql
#4.修改配置文件
vim /etc/mysql/my.cnf
datadir = /data/mysql
#5.修改启动文件
vim /etc/apparmor.d/usr.sbin.mysqld
#把
/var/lib/mysql r
/var/lib/mysql/** rwk
#修改成
/data/mysql r
/data/mysql/** rwk,
#6.重启服务，即重启apparmor
/etc/init.d/apparmor restart
/etc/init.d/mysql restart

设置max_connect，这个值与很多相关，包括ubuntu设置的最大打开文件数等，设置请看《新开ubuntu的必要优化》。
然后设置mysql.service文件：

vi /lib/systemd/system/mysql.service

最后增加两行：

LimitNOFILE=102400
LimitNPROC=102400

运行systemctl daemon-reload
再进入mysql检查下

show variables like "max_connections";