Balance web application server traffic How to do decentralized processing

Today, about the server is generally concerned about the work, because many people use the network, so the server traffic is often the state of the load, which is not good for the work, so the wandering on the server is best to be scattered . The web application server cluster system is a cluster system consisting of a group of servers running the same web application at the same time. It seems to be a server in the outside world. In order to balance the load of the cluster server and optimize the performance of the system, the cluster server distributes many access requests to different nodes in the system for processing. This results in greater effectiveness and stability, which is a must-have feature for web-based enterprise applications.

First, the two methods of calculating the WEB server load

The web application server cluster system is a cluster system consisting of a group of servers running the same web application at the same time. It's like a server. In order to balance the load of the cluster server and optimize the performance of the system, the cluster server distributes many access requests to different nodes in the system for processing. This results in greater effectiveness and stability, which is a must-have feature for web-based enterprise applications.

High reliability can be seen as a redundant setting for the system. For a specific request, if the requested server can't process it, can other servers handle it effectively? For an efficient system, if one web server fails, other servers can replace it immediately. The location, the request is processed, and the process is as transparent as possible to the user, making the user undetectable!

Stability determines whether the application can support the growing The number of user requests, which is a capability of the application itself. Stability is an effective measure of the many factors that affect system performance, including the maximum number of simultaneous users accessing the system that the cluster system can support and the time it takes to process a request.

In the existing methods of balancing server load, the following two methods are widely studied and used:

DNS load balancing method RR-DNS (Round-Robin Domain Name System) )

Load Balancer

Below, we will discuss these two methods.

Second, the advantages and disadvantages of DNS rotation scheduling

The data file in the Domain Name Server maps the host name to its IP address. When you type a URL into your browser, the browser sends the request to the DNS asking it to return the IP address of the corresponding site. This is called a DNS query. When the browser obtains the IP address of the site, it connects to the site to be accessed through the IP address, and presents the page to the user.

A Domain Name Server (DNS) usually contains a single IP address with a list of the names of the sites to which the IP address is mapped. In our example of the above illusion, the mapped IP address of a certain site is 203.24.23.3.

In order to use the DNS to balance the load of the server, for the same site, there are several different IP addresses in the DNS server. These IP addresses represent different machines in the cluster and are logically mapped to the same site name. This can be better understood by our example. The site will be published to three machines in a cluster through the following three IP addresses:

The following is the reference:

203.34.23.3

203.34.23.4

203.34.23.5

In this example, the DNS server contains the following mapping table:

www.loadbalancedsite .com 203.34.23.3

www.loadbalancedsite.com 203.34.23.4

www.loadbalancedsite.com 203.34.23.5