Hello,
Well I'm sure by now most of you have read the Web Server Optimization Guide by Shaw Networks. It came in handy for me when I was first starting out, I reduced my load & memory usage by tonnes. I thought I would make a new thread with an updated How-To.

Recommended Tools/Programs:
Putty - Free SSH Client - http://www.putty.nl/download.html
WinSCP - Free SFTP and SCP Client - http://winscp.net/eng/index.php


MySQL Optimization:
BACKUP:
cp /etc/my.cnf /etc/my.cnf.backup

Use Pico (pico /etc/my.cnf) or Download via WinSCP for editing,
Delete everything that is currently in the file and add the following...

Code:
Code:
[mysqld]
port = 3306
socket = /var/lib/mysql/mysql.sock
skip-locking
skip-innodb
query_cache_limit=8M
query_cache_size=256M
query_cache_type=1
max_connections=500
max_user_connections=100
interactive_timeout=60
wait_timeout=60
connect_timeout=30
thread_cache_size=128
key_buffer=16M
join_buffer=1M
max_allowed_packet=16M
table_cache=1024
record_buffer=1M
sort_buffer_size=2M
read_buffer_size=2M
max_connect_errors=100
# Try number of CPU's*2 for thread_concurrency
thread_concurrency=2
myisam_sort_buffer_size=64M
#log-bin
server-id=1

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash

[isamchk]
key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

[myisamchk]
key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeoutTo Save: CTRL-X
Restart Service: "service mysqld restart" or "service mysql restart" or "/etc/rc.d/init.d/mysql restart"

HTTP/APACHE Optimization:

BACKUP:
cp /usr/local/apache/conf/httpd.conf /usr/local/apache/conf/httpd.conf.backup

Use Pico (pico /usr/local/apache/conf/httpd.conf) or Download via WinSCP for editing,
Change the following settings in your httpd.conf...

Set "Timeout" value to "Timeout 60"
Set "KeepAlive" to "KeepAlive on"
Set "KeepAliveTimeout" to "KeepAliveTimeout 3"
Set "MinSpareServers" to "MinSpareServers 16"
Set "MaxSpareServers" to "MaxSpareServers 32"
Set "MaxRequestsPerChild" to "MaxRequestsPerChild 256"
Set "HostnameLookups" to "HostnameLookups Off"

Note:
These settings will not work under all server environments its recommended that you tweak around with the numbers until your web server is running 100% please read Apache documentation before changing any settings so you know what you are changing http://httpd.apache.org/docs/

To Save: CTRL-X
Restart Service: "service httpd restart" or "/etc/rc.d/init.d/httpd restart"


Installing eAccelerator:
eAccelerator is a further development from mmcache PHP Accelerator & Encoder. It increases performance of PHP scripts by caching them in compiled state, so that the overhead of compiling is almost completely eliminated. http://eaccelerator.net/

If you run CPanel please visit eAccelerator auto installer - for cPanel : Technical and Security Tutorials : Web Hosting Talk for an auto-installer which will do all the hard work for you.

Run the following in SSH.

Code:
Code:
cd /

mkdir ea

cd ea

wget http://optusnet.dl.sourceforge.net/s...-0.9.5.tar.bz2

bunzip2 eaccelerator-0.9.5.tar.bz2
tar -xvf eaccelerator-0.9.5.tar

cd eaccelerator-0.9.5

export PHP_PREFIX="/usr"

$PHP_PREFIX/bin/phpize

./configure --enable-eaccelerator=shared --with-php-config=$PHP_PREFIX/bin/php-config

make

make install

mkdir /phpcache

chmod 0777 /phpcache
Edit your PHP.INI file and at the bottom add...

Code:
Code:
To install as a ZEND extension:

zend_extension="/ea/eaccelerator-0.9.5/modules/eaccelerator.so"
eaccelerator.shm_size="16"
eaccelerator.cache_dir="/phpcache"
eaccelerator.enable="1"
eaccelerator.optimizer="1"
eaccelerator.check_mtime="1"
eaccelerator.debug="0"
eaccelerator.filter=""
eaccelerator.shm_max="0"
eaccelerator.shm_ttl="0"
eaccelerator.shm_prune_period="0"
eaccelerator.shm_only="0"
eaccelerator.compress="1"
eaccelerator.compress_level="9"

OR to install as a PHP extension:

extension="/ea/eaccelerator-0.9.5/modules/eaccelerator.so"
eaccelerator.shm_size="16"
eaccelerator.cache_dir="/phpcache"
eaccelerator.enable="1"
eaccelerator.optimizer="1"
eaccelerator.check_mtime="1"
eaccelerator.debug="0"
eaccelerator.filter=""
eaccelerator.shm_max="0"
eaccelerator.shm_ttl="0"
eaccelerator.shm_prune_period="0"
eaccelerator.shm_only="0"
eaccelerator.compress="1"
eaccelerator.compress_level="9"
Restart Service: "service httpd restart" or "/etc/rc.d/init.d/httpd restart"

For a great tutorial on Optimizing host.conf & sysctl.conf visit..
http://www.eth0.us/node/104

Common SSH Commands visit..
http://www.webhostgear.com/35.html

How to block an IP using iptables visit..
http://www.netadmintools.com/part216.html