This article descripes some optimal settings when running apache on a VPS whith limited memory. The setup was testet on a VPS server from Surftown with aprox 1Gb memory. The symptoms was from time to time slow performance on the hosted websites. CPU usage was low, and memory utilization looked fine. These settings can probably help solving performance issues.

First install the package apache-mpm-fork

$ apt-get install apache-mpm-fork

Then edit the /etc/apache2/apache.conf and find the following section and overwrite it with these settings.

<IfModule mpm_worker_module>
StartServers       2
MaxClients        50
MinSpareThreads    2
MaxSpareThreads    4
    ThreadsPerChild      25
    MaxRequestsPerChild   5000
</IfModule>

Now restart apache

$ /etc/init.d/apache2 restart

And you're done.