[+/-HS] Optimiser un serveur Mysql

[Francois Sauterey <Francois@sauterey.org>]

J'ai un petit soucis avec un serveur Mysql, et peut-être y aura-t-il ici un 
spécialiste ?
J'ai une machine sous Debian-Sarge qui fait serveur Apache2 hébergeant +/- 500 
sites différents dont la moitié à peu près en php/mysql.
Une autre (sur un réseau interne en 100M) est le serveur Mysql.
Cette dernière, toujours debian-Sarge, 512Mo de mem, refuse régulièrement les 
connexions.
(un mysqladmin ping en boucle [pas de 5 secondes]  donne en gros un refus par 
minute]
Je cherche à optimiser les (nombreux) paramètres de MysqlServer.

Ci-joint, mon my.cnf...

@micalement,
-- 
Francois Sauterey
@: Francois_AT_Sauterey.org

# My.cnf
#
# inspiré de /usr/share/doc/mysql-server/examples/my-large.cnf.gz
#
# This is for a large system with memory = 512M where the system runs mainly
# MySQL.
#

# The following options will be passed to all MySQL clients
[client]
#password	= your_password
port		= 3306
socket		= /var/run/mysqld/mysqld.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port		= 3306
socket		= /var/run/mysqld/mysqld.sock
skip-locking
key_buffer = 256M
max_allowed_packet = 1M
table_cache = 256
sort_buffer_size = 1M
read_buffer_size = 1M
myisam_sort_buffer_size = 64M
thread_cache = 8
query_cache_size= 16M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8

# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
#log            = /var/log/mysql.log
#log             = /var/log/mysql/mysql.log
# Replication Master Server (default)
# binary logging is required for replication
#log-bin


# Uncomment the following if you are using BDB tables
#bdb_cache_size = 64M
#bdb_max_lock = 100000

# 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
#innodb_buffer_pool_size = 256M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 64M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[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