Apache is a widely used open source web server that can be customized through modules to suit various use cases. It was originally developed by Rob McCool at the National Center for Supercomputing Applications (NCSA) and has since become the most popular web server in use today, with approximately 45% of active sites running on it. Apache's modular architecture allows developers to create and contribute their own modules without affecting the core functionality of the server. The server's performance can be monitored using various key performance metrics such as request processing time, rate of requests, resource utilization and activity metrics, host-level resource metrics, memory usage, CPU utilization, open file descriptors, client error rate, and server error rate. By monitoring these metrics, users can identify bottlenecks or performance problems before they manifest themselves as user-facing issues and take measures to optimize the server's performance. The event MPM is a more efficient way of handling keep-alive connections, while lowering the number of processes created upon startup or decreasing MaxSpareThreads can help lower memory footprint. Monitoring errors such as 4xx client errors and 5xx server-side errors can also provide useful indicators of underlying problems or misconfigured files.