Million-level PHP website architecture technology revealed

Million-level PHP website architecture technology revealed_PHP tutorial

WBOY

Release： 2016-07-13 17:39:35

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After learning about the world’s largest PHP site, Facebook’s backend technology, today we will learn about the website architecture of a million-level PHP site: Poppen.de. Poppen.de is a social networking site in Germany. It is a small website compared to Facebook and Flickr, but it has a good architecture and integrates many technologies, such as Nigix, MySql, CouchDB, Erlang, Memcached, RabbitMQ, PHP, Graphite, Red5 and Tsung.

Statistical information

　◆2 million registered users;

　◆20,000 concurrent users;

　◆200,000 private messages per day;

　◆250,000 logins per day;

　◆The project team has 11 developers, two designers, and two system administrators;

Business Model

This website adopts a freemium model, and users can use any of the following services for free:

　◆Search other users;

　◆Send a message to your friends;

　◆Upload pictures and videos;

　◆Find friends;

　◆Video chat;

　◆More…

But if users want to enjoy unlimited messaging and uploading pictures, they have to pay for different types of membership services according to their needs. The same strategy is used for video chat and other services on the website.

Toolbox

Nginx

All services of Poppen.de are based on Nginx service. The front end has two Nginx servers serving a load of 150,000 requests per minute at peak times. Each machine is four years old and has only one CPU and 3GB of RAM. Poppen.de has three independent image servers, and three Nginx servers provide *.bilder.poppen.de with 80,000 request services per minute.

A cool design in the Nginx architecture is that many requests are handled by Memcached, so requests get content from the cache without directly accessing the PHP machine. For example, user information pages (user profiles) are content that requires intensive processing on the website. If all user information pages are cached on Memcached, then the request will directly obtain the content from Memcached. Poppen.de's Memcached can handle 8,000 requests per minute.

There are three Nginx image servers in the architecture to provide local image caching, and users upload images to a central file server. When an image is requested from one of the three Nginx, if the image does not exist locally on the server, it will be downloaded from the central file server to the server for caching and service. This load-balanced distributed image server architecture design can reduce the load on primary storage devices.

PHP-FPM

This website runs on PHP-FPM. There are a total of 28 PHP machines with dual CPUs and 6GB of memory, each running 100 PHP-FPM worker threads. Using PHP5.3.x with APC enabled. PHP5.3 can reduce CPU and memory usage by more than 30%.

　The program code is developed based on the Symfony1.2 framework. One is that external resources can be used, and the other is that it can improve project development progress, and at the same time, it can make it easier for new developers to join the team on a well-known framework. Although nothing is perfect, you can get a lot of benefits from the Symfony framework, allowing the team to focus more on Poppen.de's business development.

Website performance optimization uses XHProf, which is a class library open sourced by Facebook. This framework is very easy to personalize and configure, and can cache most expensive server calculations.

MySQL

　MySQL is the main RDBMS for websites. The website has several MySql servers: a 4CPU, 32GB server stores user-related information, such as basic information, photo description information, etc. This machine has been used for 4 years, and the next step is to replace it with a shared cluster. The design is still based on this system to simplify the data access code. Data partitioning is based on user ID, because most of the information in the website is user-centered, such as photos, videos, messages, etc.

There are three servers providing user forum services based on a master-slave-slave configuration architecture. A slave server is responsible for storing custom messages on the website, and there are currently 250 million messages. The other four machines are in a master-slave configuration. In addition, four machines are configured into an NDB cluster to specifically serve intensive write operation data, such as user access statistics.

The data table design should try to avoid association operations and cache as much data as possible. Of course, the structural specifications of the database have been completely destroyed. Therefore, to make searching easier, database design creates data mining tables. Most of the tables are MyISAM-type tables, which can provide fast search. The problem now is that more and more tables have been fully locked. Poppen.de is considering migrating to the XtraDB storage engine.