Overview
Apache HTTP Server is a classic web server with a multi-process architecture. OpenLiteSpeed (OLS) is an event-driven, open-source version of the commercial LiteSpeed Web Server.
| Parameter | Apache | OpenLiteSpeed |
|---|---|---|
| Architecture | Process/Thread (MPM) | Event-driven |
| .htaccess Support | Full, real-time | Partial, requires restart |
| PHP Processing | mod_php, PHP-FPM | Native LSAPI (faster than FPM) |
| HTTP/3 (QUIC) | Via third-party modules | Native support |
| Control Panel | None (CLI) | WebAdmin GUI (port 7080) |
Performance
Apache uses a One Connection per Process/Thread model. As concurrent requests increase, this leads to high RAM consumption and CPU context switching. In static content tests, Apache delivers up to 15,000-20,000 requests per second on standard hardware.
OpenLiteSpeed uses non-blocking I/O, similar to Nginx. Thanks to the LSCache module and LSAPI protocol, OLS processes PHP scripts 20-50% faster than Apache with PHP-FPM. In WordPress scenarios, OLS handles 3-5 times more simultaneous connections with comparable resources.
Configuration & complexity
Apache configuration is based on httpd.conf text files. The main feature is .htaccess files, which allow directory settings to be changed without restarting the server. This is convenient but slows down the file system due to constant checks for the file's existence.
OpenLiteSpeed is configured via a web interface or XML files. OLS reads .htaccess rules but does not track changes dynamically. After editing rules, a restart is mandatory: systemctl restart openlitespeed. This makes OLS less flexible for mass Shared hosting but more performant.
When to choose what
- Apache: if a specific module is required (e.g., mod_passenger for Ruby), a complex .htaccess hierarchy is used, or maximum compatibility with legacy panels (cPanel, DirectAdmin) is essential.
- OpenLiteSpeed: for high-load WordPress, Magento, or PrestaShop sites. Ideal for VPS with limited resources where you need to squeeze the most out of 1-2 GB of RAM.
Cost / licensing
Both products are free. Apache is shipped under Apache License 2.0. OpenLiteSpeed is distributed under the GPL v3 license. The main difference between OLS and the paid Enterprise version is the lack of full control panel compatibility without plugins and limitations in reading some Apache configurations.
Ecosystem & integrations
Apache has the largest module library (over 150 official ones). It is integrated into all Linux distributions by default. OpenLiteSpeed is actively promoted through the CyberPanel and has best-in-class caching plugins for popular CMSs that interact directly with the server core.
Verdict
Apache remains the standard for versatile solutions and flexible environment tuning. OpenLiteSpeed is a specialized tool for achieving maximum RPS in PHP applications with minimal latency.