It is essential to tune Apache's MaxRequestWorkers setting to mitigate the risk of resource usage problems that could lead to a crash and to ensure that your server can use the resources available to it.
If you see the following in the Apache error log, it is an indicator that you will need to adjust the MaxRequestWorkers setting:
AH00286: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting
You can search for this message with the following command:
grep MaxRequestWorkers /etc/apache2/logs/error_logweb