Recently my Ubuntu Apache server crashed during a busy period on the site, one of the last events logged was:

[error] server reached MaxClients setting, consider raising the MaxClients setting.

The default for MaxClients in apache2.conf is 100. The log suggested raising this value, many sites I Googled up suggested raising the value too. There’s also a fair amount of confusion about the correct setting for StartServers, MinSpareServers and MaxSpareServers values.