Web Servers in AWS: Performance Tune Apache 2.x

09 Jan 2013

Help determine your Apache ServerLimit and MaxClients for your specific server configuration to ensure that your instance runs smoothly.

Oftentimes when we fire up a new AWS instance we use the t1.micro type. The default Apache configuration does not take the limited resources of this instance type into account. The t1.micro instances also come without a swap partition which may cause trouble once your instance run out of RAM. If you are running MySQL or memcached on the same server you will sooner or later notice that MySQL has stopped responding because the operating system killed it.

Use the following simple script to determine your Apache ServerLimit and MaxClients:

The script will output something similar to this:

You would then modify your Apache configuration accordingly:

The above configuration excerpt assumes that you are using mod_prefork and that you want to keep some free RAM for other processes such as MySQL.