Features and functions of Ngin as an HTTP server

Nginx, as an HTTP server, has the following basic features: (Recommended learning: nginx tutorial)

Process static files, index files and automatic indexing; open file descriptor buffering.

Cacheless reverse proxy acceleration, simple load balancing and fault tolerance.

FastCGI, simple load balancing and fault tolerance.

Modular structure. Including filters such as gzipping, byte ranges, chunked responses, and SSI-filter. If multiple SSIs present in a single page are processed by FastCGI or another proxy server, this processing can run in parallel without waiting for each other.

Supports SSL and TLSSNI.

Nginx is specially developed for performance optimization. Performance is its most important consideration, and implementation pays great attention to efficiency. It supports the kernel Poll model and can withstand high load. Reports indicate that it can support up to 50,000 concurrent connections.

Nginx has high stability. When other HTTP servers encounter access peaks, or someone maliciously initiates a slow connection, it is also likely to cause the server's physical memory to be exhausted, frequent swapping, and loss of response, and the server can only be restarted.

For example, once the current apache reaches more than 200 processes, the web response speed will be obviously very slow. Nginx adopts staged resource allocation technology, making its CPU and memory usage very low.

Nginx officially states that it maintains 10,000 inactive connections. It only occupies 2.5M of memory, so attacks like DOS are basically useless to Nginx. In terms of stability, Nginx is better than lighthttpd.

Nginx supports hot deployment. It is particularly easy to start up, and can run almost 24/7 without needing to be restarted even if it runs for several months. You can also upgrade the software version without interrupting service.

Nginx adopts the master-slave model, which can make full use of the advantages of SMP and reduce the blocking delay of worker processes in disk I/O. When using select()/poll() calls, you can also limit the number of connections per process.

Nginx code quality is very high, the code is very standardized, the techniques are mature, and the module expansion is also easy. Particularly worth mentioning are the powerful Upstream and Filter chains. Upstream lays a good foundation for writing modules such as reverse proxy and communication with other servers.

The coolest part of the Filter chain is that each filter does not have to wait for the previous filter to complete execution. It can use the output of the previous filter as the input of the current filter, which is a bit like the Unix pipeline.

This means that a module can start compressing the request sent from the backend server, and can redirect the compression stream to the client before the module has received the entire request from the backend server.

Nginx adopts some of the latest features provided by os such as support for sendfile (Linux2.2), accept-filter (FreeBSD4.1), TCP_DEFER_ACCEPT (Linux 2.4), thus greatly improving performance.

Of course, Nginx is still very young, and there are some problems. For example: Nginx was created by Russians. Although there were relatively few documents in the past few years, the current documentation is relatively comprehensive, with most of the information in English and Chinese. There are also many, and there are specialized books and materials available for searching.

The authors and community of Nginx are constantly working hard to improve it. We have reason to believe that Nginx will continue to share the lightweight HTTP server market at a high growth rate and will have a better future.

The above is the detailed content of Features and functions of Ngin as an HTTP server. For more information, please follow other related articles on the PHP Chinese website!