Question

what is the difference between mpm_worker module and qos module in apache 2.4

Answer 1

MPM stands for Multi-Processing Module and QoS stands for quality of service.

This Multi-Processing Module (MPM) implements a hybrid multi-process multi-threaded server. By using threads to serve requests, it is able to serve a large number of requests with fewer system resources than a process-based server. However, it retains much of the stability of a process-based server by keeping multiple processes available, each with many threads.

The most important directives used to control this MPM are ThreadsPerChild, which controls the number of threads deployed by each child process and MaxRequestWorkers, which controls the maximum total number of threads that may be launched.

The mod_qos Apache module provides control mechanisms that allow the Apache web server to provide different levels of priority to different HTTP requests.

In computer networking, the term quality of service (QoS) describes resource management rather than the quality of a service. Quality of service implements control mechanisms to provide different priority to different users, applications, and data connections. It is used to guarantee a certain level of performance to data resources. The term quality of service is often used in the field of wide area network protocols (e.g. ATM) and telephony (e.g. VoIP), but rarely in conjunction with web applications. mod_qos is a quality of service module for the Apache web server implementing control mechanisms that can provide different levels of priority to different HTTP requests.