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The World of Web Servers: Apache vs. Nginx

Introduction to Apache and Nginx

Web servers and protocols are designed to enable users to view web pages. They send a request to view a document that is accepted by the server. The host then essentially serves the document or information to the viewer. The web server plays a central role in letting you view and access web pages on your browser.

web server

Web Server Facilitating Communication Between Client and Application Servers

There are many web servers that you can use for this purpose. Among the most popular are Nginx and Apache. In fact, these servers are hosting most of the websites currently available on the internet.

Apache and Nginx are quite similar in many ways. To begin with, both of the web servers are open-source. This means that anyone in the world can use them for absolutely no cost. But there are many features that are unique to each of the servers. These special characteristics make them best suited for various applications and purposes.

To help you decide which web server is superior or ideal for you, we will compare Nginx and Apache. The comparison will be performed across a number of essential parameters that are critical for users of the web servers. Let’s start!

Basic Overview

We will begin with a general overview of the two web servers. Both Apache and Nginx have built great reputations in the community. They are heralded for their performances and used by several big-name organizations around the world.

Apache

Apache came out in 1995. Robert McCool developed this HTTP server under the Apache Software Foundation, hence the name. Ever since its release, hundreds of thousands of people around the globe have been using Apache.

Its sheer popularity means a lot of third-party software and sources collaborate with it frequently. Thus,  if you are looking for a good support network with lots of integrations, Apache is the one for you. Apache is also preferable for many people because it is more dynamic and flexible. It also offers a greater expanse of languages it can interpret.

Nginx

Nginx is a relatively newer web server, coming out in 2004. It is a result of the efforts of Igor Syosev to deal with something that is now known as the C10K problem. This issue arose when it started to become difficult for servers to handle great amounts of traffic. As more and more people started to use the internet, website servers started to get overwhelmed. The inability of these servers to handle several thousand connections at the same time caused the sites to crash and fail.

Nginx was released to attempt to solve this problem. That is why its architecture has an incredibly lightweight design, that is able to work with limited resources and hardware. While it is best suited to function with static content, it can integrate with software that can appropriately handle dynamic content as well.

Traffic Handling Capabilities

Now that we have a basic idea of each of the servers, we can dive into further detail. The first feature we will begin with is the traffic and handling capabilities of the individual servers. This is one of the major points that separates these two platforms. Their architectures work on different principles when it comes to handling multiple connections concurrently.

Apache

Apache uses something called MPM- Multi-Processing Modules. Administrators use a variety of MPMs to manipulate and modify the connection handling architecture. Part of the appeal of the Apache web server is the flexibility that its architecture offers. Such a module-based infrastructure that divides processing into individual and groups of threads makes it easier to scale and adapt to different kinds of connections.

Let’s take a look at some of the individual modules used in Apache:

  • mpm_prefork

The first one is mpm_prefork. This is a processing module that is responsible for handling the incoming requests from visitors. It creates one thread or child to handle one connection at any given time. That means that if the number of requests is less than the number of processes, mpm_prefork is pretty efficient in its function.

Requests are processed quickly since a separate child is processing each one individually. But this also means that if the number of requests exceeds the number of processes, it can slow things down considerably. As a result, the request processing step eats up a lot of RAM.

  • mpm_worker

As we already know, one thread is responsible for one connection. This module goes one step further and enables you to manage multiple threads at a time. This is a much more scalable module as compared to mpm_prefork which struggles beyond a certain threshold. New connections can hook up to a thread immediately instead of having to wait around.

  • mpm_event

Mpm_event is responsible for maintaining the keep-alive connections. The primary purpose of this module is to prevent the system from getting bogged down due to keep-alive requests. It does so by committing a thread to a connection even without the presence of an active request. The thread will remain dedicated for as long as the connection is live. Any incoming requests are transferred to unoccupied threads.

Nginx

As opposed to Apache, Nginx was built with a very specific purpose in mind. We already knew the problems that were arising with connection and scalability at this level. That is why it uses an algorithm that is asynchronous and non-blocking. It does not dedicate individual threads for each connection. Instead, Nginx produces numerous worker processes that are capable of handling thousands of connections at a time.

The working principle behind Nginx’s architecture is the fast looping mechanism. This algorithm is constantly processing events and monitoring them. This means that the processes are event-driven and each worker process is only committed to its own connections. All of the connections of a worker process are located in an event loop. Here, they coexist and undergo processing asynchronously with the other connections under this particular worker.

The major benefit of such an architecture is that it permits great capacity for scalability. This becomes especially applicable if you have limited resources or want to work with minimal hardware. Even if you are experiencing great amounts of traffic, there will be little impact on the RAM usage. This is because you are not generating individual threads for each connection.

Handling Static and Dynamic Content

Another parameter that we can use to compare the two web servers is how they handle static and dynamic content.

Apache

Apache uses a filе-based method to deal with static content. Its MPM processing system allows it to work with this conventional method.

When it comes to processing dynamic content, Apache can do it without needing assistance from any external components. You can enable the dynamic processors by loading a module. This module will process the content by analyzing the language and then embedding the relevant processor into the worker.

The major benefit of not having to use external components to process dynamic content is evident during configuration and coordination. It is much easier to only coordinate internal components with each other.

Nginx

The biggest difference between the way Apache and Nginx handle content is that Nginx is simply incapable of processing dynamic content internally. It has to be paired up with an external component to process requests for dynamic content. This means that you will need to use your Nginx server in conjunction with an external processor. The component will receive the request for PHP/dynamic content, process it, and then send it back to the server.

Since the information has to be relayed between the two components, you will need to coordinate communication between them. You will have to determine how many connections you want to allow and configure the protocol. You will have to use the protocol that can be read and understood by Nginx, such as HTTP, FastCGI, SCGI, uWSGI, or memcache among others.

On the other hand, Nginx does really well with the handling of static content. It does need help from any external sources to do so. It will also only activate the interpreter when it needs it. This is one of the benefits of using Nginx. The interpreter is not embedded in the process. This means it will only be present for the processing of dynamic content.

Content Directories: Distributed vs Centralized Configuration

Every web server has its own content directory. One of the most critical parameters on which to judge Apache and Nginx is whether or not they permit directory level configuration.

Apache

There are certain hidden files in content directories that contain directives. These are the .htaccess files. With Apache, you can interpret these directives on a per-directory basis. Thus, when you send a request, Apache will inspect the path to the file to find an .htaccess file. When it does, it will interpret and apply the directives within it immediately. Apache will not reload the server to implement these directives.

The above-defined process allows for decentralized configuration of the directories in the webserver. Decentralized configuration is useful for URL rewrites, implementing access restrictions, confirming authorizations, and setting caching policies.

One of the benefits of the .htaccess file is that the user, who does not have authentication, can control and modify at least some aspect of the content they are viewing in their browser. That is why Apache is frequently used by shared hosting providers. The service providers have authorized access to the central configuration. The clients are able to practice control over certain directories without having access to the main configuration.

If you want, it is possible for you to turn off .htaccess interpretation in Apache.

Nginx

Unlike Apache, Nginx does not work with any .htaccess files. This makes it comparatively less flexible. However, Nginx brings a number of improvements in its configuration style instead. To begin with, it is able to process requests at a much faster rate than Apache. This is because it is not searching for, reading, interpreting, and then implementing each .htaccess file it finds in its path. Instead of searching each parent directory, Nginx only does one directory lookup for one request.

Additionally, Nginx has a major security advantage over Apache. Nginx does not hand over any part of the configuration of the content directories to individual users, unlike Apache. While you may be maintaining strict security measures, who says the individual users are able to do the same? With Nginx, you retain control over the security status and configuration of the entire directory network.

Request Interpretation

Another way to differentiate between the two servers is the way they interpret requests.

Apache

When the server receives a request, it interprets it and then connects it to the relevant system resources. It interprets the request either as a physical resource on the filesystem or as a URI location.

When interpreting as a physical resource, it uses the <Directory> or <Files>  blocks. This is the default interpretation method for the server. It takes the root of the document. Then, it follows the host and port number in the request to find the relevant file in the document tree.

The URI location, on the other hand, needs an abstract evaluation. So Apache employs the <Location> blocks for abstract resources instead of working with the filesystem.

There are a number of other alternatives to using the default file-based system apart from URI. For example, you can use the Alias directive to find an alternative location to map to. You can also make use of expression variants to make filesystem configuration more flexible.

Nginx

Where Apache was born to be a web server, Nginx serves dual roles as a web as well as a proxy server. That is why instead of leaning towards the file system, Nginx prefers to work with URIs. You can visualize the preference from the fact there is no way for you to specify configuration for a filesystem directory in Nginx. It can, however, translate to the filesystem if and when required.

Server and location are the configuration blocks that are primarily used in Nginx. The former interprets the host that is being requested. The latter matches the URI portions after the host and the port. As a result, the server interprets the request as a URI location instead of an actual file on the system.

Because of its URI based interpretation system, Nginx is able to serve its role as a web server, a proxy server, and a mail server. Since it does not refer to the filesystem while interpreting the request, it is understandable why it does not implement .htaccess files either.

Module Systems

While both Apache and Nginx offer support module systems for an extension, there are some major differences in their inner workings.

Apache

With Apache, you can dynamically load and unload modules when running the server. The core remains at the center of the processes and the modules serve to extend functionality. You can use these attachable modules to accomplish a number of tasks. The options are practically endless with Apache’s vast library.

In fact, you can even modify the function of the server core by using modules like  mod_php. As we have mentioned before, this module allows you to embed a PHP interpreter into the individual worker processes. This is useful when you need to process dynamic content.

But the story does not end there. You can also add modules to enable functions such as client authentication, server hardening, caching, URL rewriting, proxies, rate limiting, compression, as well as encryption.

Nginx

The module system of Nginx is different in the sense that you cannot dynamically load the modules onto the main server. Instead, they have to be collected and compiled on the core software. This leaves much to be desired in terms of flexibility and ease of use. While the distribution packages have some common modules, you will have to build the server for other modules. Therefore, you need to know how to maintain your compiled software outside of the traditional packaging system.

Regardless, the advantage of this non-standard module system is that it gives you a high degree of specificity. You can customize your modules by only incorporating the functionalities that you require. It lets you leave behind the components that you don’t need and save yourself front the security risk in the process. At the same time, you can accomplish the same tasks with Nginx modules as you can with Apache. Those include URL rewriting, logging, authentication, and so forth.

Ecosystem and Support

Integrations and software support are very important when it comes to web servers. Next, we will explore the compatibility and support that is available for Apache and Nginx.

Apache

Apache is an older and more popular platform. Thus, it is understandable that it has a greater array of supportive tools and software in comparison to Nginx. There is a tonne of third-party documentation at your disposal to support the core server. Not only that, but you can also pair it with other software to accomplish specific tasks. You can either add these tools to your project or your package. They are able to bootstrap easily within the Apache ecosystem.

Nginx

While Nginx is behind Apache in this regard, it is certainly doing its best to catch up. More and more individuals are picking up Nginx as they realize its full potential. Support for the platform continues to rise alongside its organic growth as a useful, fast processing web server.

One of the major support hurdles that Nginx had to cross was finding documentation in the English language. This is because a majority of Nginx was originally written in the Russian language, including most of its documentation. However, as the server has spread and become more renowned, plenty of third-party resources are now available in the universal language.

A Collaborative Solution?

Now, you have a much better grasp of the essential components and inner workings of Apache and Nginx. While they are quite different from each other, some users capitalize on this fact to make the best of both worlds. That’s right- it is possible for you to use Apache and Nginx together.

Conventionally, users tend to use Nginx as a reverse proxy and place it in front of Apache. This allows you to make up for the lack of speed in Apache’s request handling and processing. Nginx takes in and handles all the requests while it is at its fastest. It also enables you to quickly deal with a large number of requests concurrently without having to invest a lot of resources.

Another Nginx feature that users capitalize on is its ability to handle static content efficiently. To make up for the fact that Nginx needs an external component to process dynamic content, we can refer PHP and other relevant requests over to Apache through a proxy. Apache will render the request into a web page and send it back to Nginx so that it may serve the client.

Here are some resources you can find on our blog that can get you started on both web servers:

Apache
Nginx

Conclusion

At the end of the day, both Apache and Nginx have their strengths and weaknesses. There are no hard and fast rules or recommendations for which server you should use for your project. You are the best judge of what works best for your application based on your unique requirements.

You need to find out the aspects and features that you cannot compromise on and choose accordingly. If it is hard to make the decision, you can always turn to using both servers together in a customized solution.

Happy Computing!