I would like to start by saying that this article is not necessary meant for cPanel powered servers but I will make all my references to this type of servers. You can still apply all the tips here to all apache based webservers so don’t stop reading here if you don’t have cPanel !

OK, lets start.
First login to your server as root using ssh.

All the important configuration options are stored by Apache in a config file called httpd.conf that is located at /usr/local/apache/conf/httpd.conf We will start by opening this file in your favorite text editor. For exemple:

nano /usr/local/apache/conf/httpd.conf

• MaxClients - Total number of concurrent connections.
  Locate it in the configuration file. This should be set to a reasonable value. I suggest using this formula to determine the right value for your server.

MaxClients = 150 x RAM (GB)

So for example if you have 2 GB or RAM set this value to 300.
There is no reason for you to set it any higher unless you have a specific problem with this value. A high value can lead to a complete server hang in case of a DOS attack. A value too low can create timeout problems for your clients if the limit is reached.

• MinSpareServers and MaxSpareServers - MaxSpareServers and MinSpareServers control how many spare (unused) child-processes Apache will keep alive while waiting for more requests to put them to use. Each child-process consumes resources, so having MaxSpareServers set too high can cause resource problems. On the other hand, if the number of unused servers drops below MinSpareServers, Apache will fork (an expensive operation) new child-processes until MinSpareServers is satisfied.

Leave those values to:

MinSpareServers 5
MaxSpareServers 10

If you have more them 2 GB of RAM and you run a resource intensive website consider increasing MaxSpareServers.

• MaxRequestsPerChild – Controls the number of request the a child serves before the child is killed. This should not be set too low as it will put an unnecessary load on the apache server to recreate the child. I suggest setting it to:

MaxRequestsPerChild 1000

• KeepAlive and MaxKeepAliveRequests – KeepAlive provides long-lived HTTP sessions which allow multiple requests to be sent over the same TCP connection. In some cases this has been shown to result in an almost 50% speedup in latency times for HTML documents with many images, but having keepalive on is also a resource intensive setting.
  Here comes the big question: To KeepAlive or not to KeepAlive?
  
  Well the opinions are mixed here, some say to KeepAlive some say not to.
  If you want to hear my option I would say NOT to KeepAlive if you are running a shared hosting business or if you want to get the most out of your hardware. You should KeepAlive only if the loading time of your pages is the most important factor in your business and you have the money to invest in a more powerful hardware. If you decide to KeepAlive I suggest you set MaxKeepAliveRequest low to something like 2 seconds.
• StartServers – Sets the number of child server processes created on startup. This setting depends greatly on the type of webserver you run. If you run low traffic websites on that server set it low to something like 5. If you have resource intensive websites on that server you should set it close to MaxClients.
• Timeout - The amount of time Apache will wait for three things: the total amount of time it takes to receive a GET request, The amount of time between receipt of TCP packets on a POST or PUT request, the amount of time between ACKs on transmissions of TCP packets in responses.
  The default value is 300. You should set time to something a bit lower. A setting of 150 is probably ok. This will also help in case of small DOS attacks like to ones targeting some phpBB forums. Do NOT set it any lower then 90 as your users will start having timeout problems.

After you have done all the necessary changes you can go ahead and restart Apache.

service httpd restart

It should restart without any problems. If it doesn’t please double check the changes that you done.

Important Notice ! After upgrading to cPanel 11 and recompiling Apache there is an extra step that you have to do so that the changes that you done to httpd.conf aren’t lost.
Starting with cPanel 11.x all the apache setting are also stored in a database and the configuration files are recreated each time an account is added or a recompile is done.

To also save the changes in the database you will have to run:

/usr/local/cpanel/bin/apache_conf_distiller –update

You can check to see if the changes were accepted and will not be discarded at the next apache recompile by running

/usr/local/cpanel/bin/build_apache_conf

Hope this article will help a lot a people. I would like to hear your feedback on this, so please leave a comment !

MySQL can log those queries that are taking longer then X seconds but this future is not turned on by default.
Here’s how you turn it on:

1. Login to your server as root
2. Open my.cnf with your favorite editor. Example:

pico /etc/my.cnf

3. Into the [mysqld] section add the fallowing lines

log-slow-queries = /var/log/mysql-slow.log
long_query_time = 3

This is just an example. You can use any file name that you want and you can modify the long_query_time to any value. In this example I will be logging to /var/log/mysql-slow.log any queries that are taking longer then 3 seconds.

4. Go ahead and save the configuration.

For pico: CTRL+X and YES

5. Now we have to actually create the log file.

touch /var/log/mysql-slow.log

6. Now we are changing the owner of the file so that mysql and actually write to it.

chown mysql.root /var/log/mysql-slow.log

7. Now we restart mysql

service mysql restart

It should restart successfully. If it doesn’t check that you didn’t brake my.cnf

8. Wait a few minutes and then examine the slow queries log

A few examples on how to do it:


cat /var/log/mysql-slow.log
tail /var/log/mysql-slow.log
tail -50 /var/log/mysql-slow.log

After you have identified the offending query go ahead and optimize or remove it.
Again test the results by looking at your server load and the mysql slow queries log.

After you fixed all the problems go ahead and comment the slow queries logging as it will slow your server a bit if you let it on. my.cnf should now look similar to this:

#log-slow-queries = /var/log/mysql-slow.log
#long_query_time = 3

And don’t forget to restart MySQL after this.

service mysql restart

Hope this helps !

I suggest you also read:

• Install MySQL Performance Tuning Primer Script
• Install mytop – top clone for MySQL

If you have any problems or suggestions don’t hesitate to leave a comment.

Installation is extremely simple:

1. Download the script

wget http://day32.com/MySQL/tuning-primer.sh

2. Change the permissions for the file
   

   chmod 755 tuning-primer.sh

3. Run it

./tuning-primer.sh

4. Apply the sugesttions

Enjoy!

You will find more details on the homepage at http://jeremy.zawodny.com/mysql/mytop/

How to install

1. Download mytop

wget http://jeremy.zawodny.com/mysql/mytop/mytop-1.6.tar.gz

2. Extract and change directory

tar -zxvf mytop-1.6.tar.gz
cd mytop-1.6

3. Install mytop

perl Makefile.PL
make
make install

4. Run mytop

mytop

You can find additional information about mytop configuration at: http://jeremy.zawodny.com/mysql/mytop/mytop.html

1. Login to the server as root
2. Download APC

wget http://pecl.php.net/get/APC-3.0.14.tgz

3. Extract and move into the directory

gzip -d APC-3.0.14.tgz
tar -xf APC-3.0.14.tar
cd APC-3.0.14

4. Locate where php is

which php

This should return something like: /usr/local/bin/php
We have to remember the location of php

5. Create configuration files

phpize

6. Compile APC

./configure –enable-apc –enable-apc-mmap –with-apxs –with-php-config=/usr/local/bin/php-config
make
make install

The “make install” commnand will return the location of the apc.so extention please note the location. You will need this later.


7. Install APC into php.ini

You will have to first locate php using the locate command

locate php

This will usualy return /usr/local/Zend/etc/php.ini on a server that has Zend optimizer installed.
Now we will edit php.ini and add the APC extension.

pico /usr/local/Zend/etc/php.ini

Scroll down to the buttom and add the fallowing before the lines about the zend optimizer (They start with [Zend])

extension=”/apc_location/apc.so”

8. Restart Apache

If you done everything it’s time to restart Apache

service httpd restart

Hope this helps !

What is Eaccelerator?
eAccelerator is a free open-source PHP accelerator, optimizer, and dynamic content cache. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution. eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 times.

Install instructions

1. Login as root
2. Download Eaccelerator

wget http://bart.eaccelerator.net/source/0.9.5.2/eaccelerator-0.9.5.2.zip

3. Extract and move into the directory

unzip eaccelerator-0.9.5.2.zip
cd eaccelerator-0.9.5.2

4. Locate where php is

which php

This should return something like: /usr/local/bin/php
We have to remember the location of php

5. Create configuration files

phpize

6. Compile Eaccelerator

./configure –enable-eaccelerator=shared –with-php-config=/usr/local/bin/php-config
make
make install

The “make install” commnand will return the location of the eaccelerator.so extention please note the location. You will need this later.


7. Install Eaccelerator into php.ini

This can be done as a Zend extension or as a PHP extention.
I personally recommend installing it as a Zend extension.
You will have to first locate php using the locate command

locate php

This will usualy return /usr/local/Zend/etc/php.ini on a server that has Zend optimizer installed.
Now we will edit php.ini and add the Eaccelerator extension.

pico /usr/local/Zend/etc/php.ini

Scroll down to the buttom and add the fallowing before the lines about the zend optimizer (They start with [Zend])

zend_extension=”/eaccelerator_location/eaccelerator.so”
eaccelerator.shm_size=”16″
eaccelerator.cache_dir=”/tmp/eaccelerator”
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″

8. Restart Apache

If you done everything it’s time to restart Apache

service httpd restart

9. Test to see if everything is ok

php -v

If you see something like you are all done.

with eAccelerator v0.9.5.1, Copyright (c) 2004-2006 eAccelerator, by eAccelerator