Large Web site technology architecture--core principles and case studies large Web site architecture Model (ii)

In terms of what a pattern is, the word from architecture is defined in this way: "Each pattern describes a problem that constantly repeats around us and the core of the solution to that problem." This way you can use the program over and over again without having to do repetitive work. " The key to the pattern is the reusability of the pattern, and the repeatability of the problem and the scenario that leads to the solution.

Perhaps the Internet product is not a random copy can be successful, innovative products can create value for users. But there are some common patterns in the website architecture, which have been verified by many large websites, and through the learning of these patterns, we can master the general ideas and solutions of large-scale website architecture. To guide our architecture design.

2.1 Architectural patterns of the site

In order to solve a series of problems and challenges such as high concurrency, massive data processing, high reliability and so on, large-scale internet companies put forward a lot of solutions in practice in order to achieve the high performance, high availability, scalability, scalability, security and other technical architecture goals. These solutions are re-used by the website, which gradually forms a large web site architecture.

2.11 Layering

Layering is one of the most common architectural patterns in enterprise application system, which splits several parts of the system in the horizontal dimension, each part is responsible for a relatively single part, and then makes up a complete system through the upper layer dependency and invocation.

Hierarchical structure is ubiquitous in the computer world, and the 7-Layer communication Protocol of network is a hierarchical structure, and computer hardware, operating system and application software can also be regarded as a layered architecture. In the large-scale Web site architecture also adopts the hierarchical structure, the website software system is divided into application layer, service layer, data layer.

Through layering, a large software system can be better divided into different parts, so as to facilitate the development and maintenance of division of labor; there is a certain degree of independence between the layers, as long as the maintenance of the scheduling interface unchanged, each layer can be specific problems independent evolution and development without the need for other levels corresponding to the adjustment.

However, the layered architecture also has some challenges, that is, it is necessary to rationalize the hierarchical boundaries and interfaces, and in the development process, strictly follow the constraints of the layered architecture, prohibit cross-level calls and invoke reverse calls.

In practice, it is possible to continue layering within a large hierarchical architecture, such as the application layer can be subdivided into the view layer and the business logic layer, and the service layer can be broken down into data interface and business processing.

Layered architecture is logical, on the physical deployment, the 33-tier architecture can be deployed on the same physical machine, but with the development of network services, it is necessary to separate the Layered module deployment, three-tier architecture deployed on different servers, is the site has more computing resources to respond to more and more user access.

So while the initial goal of the layered architecture model is to plan software for clear logic to facilitate development and maintenance, in the development of the website, the layered architecture is critical to support the high concurrency distributed development of the website. So in the network size is still very small when the hierarchical architecture, so that in the future to do a bigger site can be better to deal with.