Server Optimization for board with 2500 to 5000 users online

[Venomrush]

My dedicated server has been responding extremely slow the past few days.
Would like to know how I can improve with your advanced knowledge on server optimisation.

Server specs:
Intel Xeon 5405 Quad Core Harpertown
Second Intel Xeon 5405 Quad Core Harpertown
RAM: 4096 MB
HDD: 146GB, 10K RPM SCSI/SAS
OS: Red Hat Enterprise Linux, Version 5

Server is only running IP.Board and nothing else.
There are about 2500 to 5000 users online every 30 minutes.
Or around 800 to 1000 per 5 minutes.

Here is my.cnf

[mysqld]

safe-show-database

skip-locking

safe-show-database

interactive_timeout=100

wait_timeout=100

connect_timeout=10

max_user_connections=25

max_connections=500

key_buffer=64M

join_buffer=2M

record_buffer=2M

sort_buffer=4M

max_allowed_packet=24M

query_cache_limit = 2M

query_cache_size = 64M

query_cache_type = 1

tmp_table_size=128M

table_cache=2048

thread_cache=256

thread_concurrency=8

[mysqld_safe]

open_files_limit = 8192

[mysqldump]

quick

max_allowed_packet = 16M

[myisamchk]

key_buffer = 64M

sort_buffer = 64M

read_buffer = 16M

write_buffer = 16M

log_slow_queries=/var/log/slow-queries.log

log-long-format

long_query_time=6

Is there anything else I can do to PHP config to help as well?

[BlakeC]

Run this script after your MySQL server has been online a day or two:

http://rackerhacker.com/mysqltuner/

It will give you some pretty good recommendations for the my.cnf values.

[rct2·com]

I've run this and it's not clear whether some of the output is recommendations are not. Examples:

Variables to adjust:

  *** MySQL's maximum memory usage exceeds your installed memory ***

  *** Add more RAM before increasing any MySQL buffer variables  ***

	sort_buffer_size (> 1M)

	read_rnd_buffer_size (> 508K)

	tmp_table_size (> 32M)

	max_heap_table_size (> 16M)

Are those recommendations for values I should set?

And how can I decrease the MySQL maximum memory usage, because adding more RAM is not an option for me?

[crafty55]

Run mysql prime tuner.

The conf posted for example the tmp table space is set wayy too low.