解决 Mysql 占用系统资源过大的问题

在 linux 下，经常出现的情况就是使用 VBB 这种论坛系统时，出现缓慢，mysql 假死状态，sleep进程过多等等现像。导致几十个用户，就把系统搞定了。
其实这是 mysql 配置上的问题， 默认的 linux 中， mysql 的配置是 my-large.cnf 配置，该配置适合大型服务器。有高内存，比如2G，4G内存的，适合使用，而一般512M内存 的就不行了。它会占用512M内存来保存系统 mysql 的进程，这些进程长期堆质，并不释放，导致系统缓慢。所以，把配置改变成为 my-small.cnf ，小型配置就可以了。它的配置如下：

# Example mysql config file for small systems.
#
# This is for a system with little memory (<= 64M) where MySQL is only used
# from time to time and it's important that the mysqld deamon
# doesn't use much resources.
#
# You can copy this file to
# /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options (in this
# installation this directory is /var/lib/mysql) or
# ~/.my.cnf to set user-specific options.
#
# One can in this file use all long options that the program supports.
# If you want to know which options a program support, run the program
# with --help option.

# The following options will be passed to all MySQL clients
[client]
#password = 你的密码
port = 3306
socket = /tmp/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port = 3306
socket = /tmp/mysql.sock
skip-locking
set-variable = key_buffer=16K
set-variable = max_allowed_packet=1M
set-variable = thread_stack=64K
set-variable = table_cache=4
set-variable = sort_buffer=64K
set-variable = net_buffer_length=2K
server-id = 1

# Uncomment the following if you want to log updates
#log-bin

# Uncomment the following if you are NOT using BDB tables
#skip-bdb

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/lib/mysql/
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql/
#innodb_log_arch_dir = /var/lib/mysql/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#set-variable = innodb_buffer_pool_size=16M
#set-variable = innodb_additional_mem_pool_size=2M
# Set .._log_file_size to 25 % of buffer pool size
#set-variable = innodb_log_file_size=5M
#set-variable = innodb_log_buffer_size=8M
#innodb_flush_log_at_trx_commit=1
#set-variable = innodb_lock_wait_timeout=50

[mysqldump]
quick
set-variable = max_allowed_packet=16M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates

[isamchk]
set-variable = key_buffer=8M
set-variable = sort_buffer=8M

[myisamchk]
set-variable = key_buffer=8M
set-variable = sort_buffer=8M

[mysqlhotcopy]
interactive-timeout


以上配置足够 你的系统高速运行 mysql 了，sleep的进程，很快就被回收，不占资源，这非常适合小型服务器。一般个人托管的服务器也很适合。