We have given some ideas about how to gain performance in some Apache tasks such as redirection.
In this post, I would like to point out some basic ideas about improving performance with an Apache server. I will refer to version 2.2. running in Ubuntu server 12.04 32 bits.
1. Activate the Apache Cache
Apache has several modules that provide cache services. This guide explains a little bit the modules available: http://httpd.apache.org/docs/2.2/caching.html.
And DigitalOcean provides a more practical look at it with straightforward tips https://www.digitalocean.com/community/articles/how-to-configure-content-caching-using-apache-modules-on-a-vps
So the simplest approach is to enable the module:
sudo nano /etc/apache2/mods-available/mem_cache.conf
where you will see the configuration. I have not changed nothing for the moment.
And then, make it run:
sudo a2enmod mem_cache
service apache2 restart
This part so far is covering the Memory Cache. I will not talk about the Disk Cache, since I am using the WordPress SuperCache plugin and would not like to have a conflict between both.
2. Allow Override none Directive
If you have set “Allow Override none” then Apache will look in every folder to find an .htaccess file. But it is most likely that you only have one .htaccess file, and not a whole cascade of .htaccess files, so, why not put it in the configuration file and save time? the benchmark shown by the excellent post by ESchrade http://www.eschrade.com/page/why-you-should-not-use-htaccess-allowoverride-all-in-production/ is very convincing. This idea is also reinforced by this post https://www.tinywp.in/move-htaccess-rule-to-apache-conf/
This action is also recommended in this great post with tips for improving Apache speed https://servercheck.in/blog/3-small-tweaks-make-apache-fly
3. Use third party cache software
If you are using WordPress, it is highly recommended to use the WordPress SuperCache Plugin. More info here http://ocaoimh.ie/wp-super-cache/
There is also a more generic option, called Varnish, https://www.varnish-cache.org/, and also a nice configuration guide by Donncha Ó Caoimh http://ocaoimh.ie/2011/08/09/speed-up-wordpress-with-apache-and-varnish/.
4. Offload unused modules
This is thoroughly explained here https://www.digitalocean.com/community/articles/how-to-optimize-apache-web-server-performance. As well as other great ideas such as
5. Reduce number of connections
Same link as above.
6. Set the right number of MaxClients
In short, this is the formula that you have to use to calculate the number of MaxClients:
(Total RAM – RAM used for Linux, MySQL, etc.) / Average httpd process size
There is a script here that will help you to get this for your server: http://cloudinservice.com/tune-apache-performance-using-mpm-prefork-module/
More details on this can be found in this link: https://servercheck.in/blog/3-small-tweaks-make-apache-fly
7. KeepAlive On or KeepAlive Off?
This is not an easy one, I have turned it to KeepAlive Off, and the server works much better now. If you want a detail explanation check out:
8. Define Spare Servers
In this post there is a useful guide for that: http://cloudinservice.com/tune-apache-performance-using-mpm-prefork-module/
Do you know of other ways of improving Apache performance? Please get in touch with us and help us complete this guide!