Passenger vs Unicorn

Overview

Unicorn

Stacks479

Followers401

Votes295

GitHub Stars1.5K

Forks269

Passenger

Stacks1.4K

Followers298

Votes199

GitHub Stars5.1K

Forks557

Passenger vs Unicorn: What are the differences?

Key differences between Passenger and Unicorn

Passenger and Unicorn are both popular application servers used for serving Ruby on Rails applications. While they are both designed to handle incoming web requests, there are several key differences between the two. The following paragraphs outline these differences in detail.

Process Management: Passenger uses a process-based approach to handle incoming requests. It spawns multiple processes to handle concurrent requests, with each process capable of serving multiple requests concurrently using multi-threading. This allows Passenger to efficiently utilize system resources and handle high traffic loads. On the other hand, Unicorn uses a multi-process, single-threaded approach. It spawns multiple worker processes, each running a single thread, to handle requests independently. This can be beneficial for certain types of applications that require a high degree of isolation between requests.
Memory Overhead: Due to its process-based approach, Passenger generally has a higher memory overhead compared to Unicorn. Each Passenger process requires its own memory footprint, which can be significant for applications with a large number of concurrent requests. In contrast, Unicorn's single-threaded worker processes have a lower memory footprint, making it more memory-efficient in certain scenarios.
Request Queueing: Unicorn provides built-in request queuing, allowing it to handle incoming requests even if all worker processes are busy. When a request arrives and all worker processes are occupied, Unicorn adds the request to a queue and serves it as soon as a worker becomes available. This can help prevent request failures during high traffic situations. In contrast, Passenger does not have built-in request queuing and relies on the web server (e.g., Nginx or Apache) to manage request queuing and load balancing.
Ease of Configuration: Passenger offers a simpler and easier configuration process compared to Unicorn. It provides a more user-friendly interface and requires fewer manual configurations, making it more suitable for developers who prefer a streamlined setup. Unicorn, on the other hand, has a more complex configuration process that requires additional steps to set up and fine-tune the server according to specific application requirements.
Integration with Web Servers: Passenger is designed to work closely with web servers like Nginx and Apache, providing tight integrations and streamlined deployment processes. It can directly communicate with the web server, allowing for efficient handling of requests and better utilization of system resources. In contrast, Unicorn operates as a separate HTTP server and requires a reverse proxy (such as Nginx or Apache) for connection to the web server, potentially adding an additional layer of complexity to the setup and configuration process.
Community Adoption: Passenger has gained significant popularity and has a large and active community of developers and users. It offers comprehensive documentation, frequent updates, and strong community support, making it easier to find resources and resolve potential issues. Unicorn, while still widely used, may have a smaller community compared to Passenger, which can limit the availability of certain resources and community-driven support.

In summary, Passenger and Unicorn differ in their process management approach, memory overhead, request queuing capability, ease of configuration, integration with web servers, and community adoption. The selection between the two depends on specific application requirements, resources availability, and developer preferences.

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Advice on Unicorn, Passenger

Mark

Software Developer at Nouveta

Mar 4, 2022

Needs adviceon

Rails

Ruby

Puma

I have an integration service that pulls data from third party systems saves it and returns it to the user of the service. We can pull large data sets with the service and response JSON can go up to 5MB with gzip compression. I currently use Rails 6 and Ruby 2.7.2 and Puma web server. Slow clients tend to prevent other users from accessing the system. Am considering a switch to Unicorn.

38.4k views38.4k

Comments

Detailed Comparison

Unicorn	Passenger
Unicorn is an HTTP server for Rack applications designed to only serve fast clients on low-latency, high-bandwidth connections and take advantage of features in Unix/Unix-like kernels. Slow clients should only be served by placing a reverse proxy capable of fully buffering both the the request and response in between Unicorn and slow clients.	Phusion Passenger is a web server and application server, designed to be fast, robust and lightweight. It takes a lot of complexity out of deploying web apps, adds powerful enterprise-grade features that are useful in production, and makes administration much easier and less complex.
Statistics
GitHub Stars 1.5K	GitHub Stars 5.1K
GitHub Forks 269	GitHub Forks 557
Stacks 479	Stacks 1.4K
Followers 401	Followers 298
Votes 295	Votes 199
Pros & Cons
Pros 81 Fast 59 Performance 36 Web server 30 Open Source 30 Very light Cons 4 Not multithreaded	Pros 43 Nginx integration 36 Great for rails 21 Fast web server 19 Free 15 Lightweight Cons 0 Cost (some features require paid/pro)
Integrations
No integrations available	NGINX Python Ruby Apache HTTP Server Node.js Meteor

What are some alternatives to Unicorn, Passenger?

NGINX

nginx [engine x] is an HTTP and reverse proxy server, as well as a mail proxy server, written by Igor Sysoev. According to Netcraft nginx served or proxied 30.46% of the top million busiest sites in Jan 2018.

Apache HTTP Server

The Apache HTTP Server is a powerful and flexible HTTP/1.1 compliant web server. Originally designed as a replacement for the NCSA HTTP Server, it has grown to be the most popular web server on the Internet.

Microsoft IIS

Internet Information Services (IIS) for Windows Server is a flexible, secure and manageable Web server for hosting anything on the Web. From media streaming to web applications, IIS's scalable and open architecture is ready to handle the most demanding tasks.

Apache Tomcat

Apache Tomcat powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations.

Gunicorn

Gunicorn is a pre-fork worker model ported from Ruby's Unicorn project. The Gunicorn server is broadly compatible with various web frameworks, simply implemented, light on server resources, and fairly speedy.

Jetty

Jetty is used in a wide variety of projects and products, both in development and production. Jetty can be easily embedded in devices, tools, frameworks, application servers, and clusters. See the Jetty Powered page for more uses of Jetty.

lighttpd

lighttpd has a very low memory footprint compared to other webservers and takes care of cpu-load. Its advanced feature-set (FastCGI, CGI, Auth, Output-Compression, URL-Rewriting and many more) make lighttpd the perfect webserver-software for every server that suffers load problems.

Swoole

It is an open source high-performance network framework using an event-driven, asynchronous, non-blocking I/O model which makes it scalable and efficient.

Puma

Unlike other Ruby Webservers, Puma was built for speed and parallelism. Puma is a small library that provides a very fast and concurrent HTTP 1.1 server for Ruby web applications.

Caddy

Caddy 2 is a powerful, enterprise-ready, open source web server with automatic HTTPS written in Go.

Related Comparisons

Passenger vs Unicorn: What are the differences?

Key differences between Passenger and Unicorn

Process Management: Passenger uses a process-based approach to handle incoming requests. It spawns multiple processes to handle concurrent requests, with each process capable of serving multiple requests concurrently using multi-threading. This allows Passenger to efficiently utilize system resources and handle high traffic loads. On the other hand, Unicorn uses a multi-process, single-threaded approach. It spawns multiple worker processes, each running a single thread, to handle requests independently. This can be beneficial for certain types of applications that require a high degree of isolation between requests.
Memory Overhead: Due to its process-based approach, Passenger generally has a higher memory overhead compared to Unicorn. Each Passenger process requires its own memory footprint, which can be significant for applications with a large number of concurrent requests. In contrast, Unicorn's single-threaded worker processes have a lower memory footprint, making it more memory-efficient in certain scenarios.
Request Queueing: Unicorn provides built-in request queuing, allowing it to handle incoming requests even if all worker processes are busy. When a request arrives and all worker processes are occupied, Unicorn adds the request to a queue and serves it as soon as a worker becomes available. This can help prevent request failures during high traffic situations. In contrast, Passenger does not have built-in request queuing and relies on the web server (e.g., Nginx or Apache) to manage request queuing and load balancing.
Ease of Configuration: Passenger offers a simpler and easier configuration process compared to Unicorn. It provides a more user-friendly interface and requires fewer manual configurations, making it more suitable for developers who prefer a streamlined setup. Unicorn, on the other hand, has a more complex configuration process that requires additional steps to set up and fine-tune the server according to specific application requirements.
Integration with Web Servers: Passenger is designed to work closely with web servers like Nginx and Apache, providing tight integrations and streamlined deployment processes. It can directly communicate with the web server, allowing for efficient handling of requests and better utilization of system resources. In contrast, Unicorn operates as a separate HTTP server and requires a reverse proxy (such as Nginx or Apache) for connection to the web server, potentially adding an additional layer of complexity to the setup and configuration process.
Community Adoption: Passenger has gained significant popularity and has a large and active community of developers and users. It offers comprehensive documentation, frequent updates, and strong community support, making it easier to find resources and resolve potential issues. Unicorn, while still widely used, may have a smaller community compared to Passenger, which can limit the availability of certain resources and community-driven support.

Passenger vs Unicorn

Overview

Passenger vs Unicorn: What are the differences?